The Wright brothers, Orville (August 19, 1871 – January 30, 1948) and Wilbur (April 16, 1867 – May 30, 1912), were two Americans who are generally credited with inventing and building the world's first successful airplane and making the first controlled, powered and sustained heavier-than-air human flight, on December 17, 1903. In the two years afterward, the brothers developed their flying machine into the first practical fixed-wing aircraft. Although not the first to build and fly experimental aircraft, the Wright brothers were the first to invent aircraft controls that made fixed-wing powered flight possible.

The brothers' fundamental breakthrough was their invention of three-axis control, which enabled the pilot to steer the aircraft effectively and to maintain its equilibrium. This method became standard and remains standard on fixed-wing aircraft of all kinds. From the beginning of their aeronautical work, the Wright brothers focused on unlocking the secrets of control to conquer "the flying problem", rather than developing more powerful engines as some other experimenters did. Their careful wind tunnel tests produced better aeronautical data than any before, enabling them to design and build wings and propellers more effective than any before. Their U.S. patent 821,393 claims the invention of a system of aerodynamic control that manipulates a flying machine's surfaces. They gained the mechanical skills essential for their success by working for years in their shop with printing presses, bicycles, motors, and other machinery. Their work with bicycles in particular influenced their belief that an unstable vehicle like a flying machine could be controlled and balanced with practice. From 1900 until their first powered flights in late 1903, they conducted extensive glider tests that also developed their skills as pilots. Their bicycle shop employee Charlie Taylor became an important part of the team, building their first aircraft engine in close collaboration with the brothers. The Wright brothers' status as inventors of the airplane has been subject to counter-claims by various parties. Much controversy persists over the many competing claims of early aviators.

The Wright brothers were two of seven children born to Milton Wright (1828–1917) and Susan Catherine Koerner (1831–1889). Wilbur Wright was born near Millville, Indiana, in 1867; Orville in Dayton, Ohio, in 1871. The brothers never married. The other Wright siblings were named Reuchlin (1861–1920), Lorin (1862–1939), Katharine (1874–1929), and twins Otis and Ida (born 1870, died in infancy). In elementary school, Orville was given to mischief and was once expelled. In 1878 their father, who traveled often as a bishop in the Church of the United Brethren in Christ, brought home a toy "helicopter" for his two younger sons. The device was based on an invention of French aeronautical pioneer Alphonse Pénaud. Made of paper, bamboo and cork with a rubber band to twirl its rotor, it was about a foot long. Wilbur and Orville played with it until it broke, and then built their own. In later years, they pointed to their experience with the toy as the initial spark of their interest in flying. Both brothers attended high school, but did not receive diplomas. The family's abrupt move in 1884 from Richmond, Indiana, to Dayton (where the family had lived during the 1870s) prevented Wilbur from receiving his diploma after finishing four years of high school.

In the winter of 1885–86 Wilbur was accidentally struck in the face by a hockey stick while playing an ice-skating game with friends, resulting in the loss of his front teeth. He had been vigorous and athletic until then, and although his injuries did not appear especially severe, he became withdrawn, and did not attend Yale as planned. Had he enrolled, his career might have taken a very different path than the extraordinary one he eventually followed with Orville. Instead, he spent the next few years largely housebound, caring for his mother who was terminally ill with tuberculosis and reading extensively in his father's library. He ably assisted his father during times of controversy within the Brethren Church but also expressed unease over his own lack of ambition.

Orville dropped out of high school after his junior year to start a printing business in 1889, having designed and built his own printing press with Wilbur's help. Wilbur shook off the lingering depression caused by his accident and joined the print shop, serving as editor while Orville was publisher of the weekly newspaper the West Side News, followed for only a few months by the daily Evening Item. One of their clients for printing jobs was Orville's friend and classmate in high school, Paul Laurence Dunbar, who rose to international acclaim as a ground-breaking African-American poet and writer. The Wrights printed the Dayton Tattler, a weekly newspaper that Dunbar edited for a brief period.

Capitalizing on the national bicycle craze, the brothers opened a repair and sales shop in 1892 (the Wright Cycle Exchange, later the Wright Cycle Company) and began manufacturing their own brand in 1896. They used this endeavor to fund their growing interest in flight. In the early or mid-1890s they saw newspaper or magazine articles and probably photographs of the dramatic glides by Otto Lilienthal in Germany. The year 1896 brought three important aeronautical events. In May, Smithsonian Institution Secretary Samuel Langley successfully flew an unmanned steam-powered model aircraft. In the summer, Chicago engineer and aviation authority Octave Chanute brought together several men who tested various types of gliders over the sand dunes along the shore of Lake Michigan. In August, Lilienthal was killed in the plunge of his glider. These events lodged in the consciousness of the brothers. In May 1899 Wilbur wrote a letter to the Smithsonian Institution requesting information and publications about aeronautics. Drawing on the work of Sir George Cayley, Chanute, Lilienthal, Leonardo da Vinci, and Langley, they began their mechanical aeronautical experimentation that year.

The Wright brothers always presented a unified image to the public, sharing equally in the credit for their invention. Biographers note, however, that Wilbur took the initiative in 1899–1900, writing of "my" machine and "my" plans before Orville became deeply involved when the first person singular became the plural "we" and "our". Author James Tobin asserts, "it is impossible to imagine Orville, bright as he was, supplying the driving force that started their work and kept it going from the back room of a store in Ohio to conferences with capitalists, presidents, and kings. Will did that. He was the leader, from the beginning to the end."

Despite Lilienthal's fate, the brothers favored his strategy: to practice gliding in order to master the art of control before attempting motor-driven flight. The death of British aeronaut Percy Pilcher in another hang gliding crash in 1899 only reinforced their opinion that a reliable method of pilot control was the key to successful — and safe — flight. At the outset of their experiments they regarded control as the unsolved third part of "the flying problem". They believed sufficiently promising knowledge of the other two issues — wings and engines — already existed. The Wright brothers thus differed sharply from more experienced practitioners of the day, notably Ader, Maxim and Langley who built powerful engines, attached them to airframes equipped with unproven control devices, and expected to take to the air with no previous flying experience. Though agreeing with Lilienthal's idea of practice, the Wrights saw that his method of balance and control — shifting his body weight — was fatally inadequate. They were determined to find something better. On the basis of observation, Wilbur concluded that birds changed the angle of the ends of their wings to make their bodies roll right or left. The brothers decided this would also be a good way for a flying machine to turn — to "bank" or "lean" into the turn just like a bird — and just like a person riding a bicycle, an experience with which they were thoroughly familiar. Equally important, they hoped this method would enable recovery when the wind tilted the machine to one side (lateral balance). They puzzled over how to achieve the same effect with man-made wings and eventually discovered wing-warping when Wilbur idly twisted a long inner-tube box at the bicycle shop.

Other aeronautical investigators regarded flight as if it were not so different from surface locomotion, except the surface would be elevated. They thought in terms of a ship's rudder for steering, while the flying machine remained essentially level in the air, as did a train or an automobile or a ship at the surface. The idea of deliberately leaning, or rolling, to one side seemed either undesirable or did not enter their thinking. Some of these other investigators, including Langley and Chanute, sought the elusive ideal of "inherent stability", believing the pilot of a flying machine would not be able to react quickly enough to wind disturbances to use mechanical controls effectively. The Wright brothers, on the other hand, wanted the pilot to have absolute control. For that reason, their early designs made no concessions toward built-in stability (such as dihedral wings). They deliberately designed their 1903 first powered flyer with anhedral (drooping) wings, which are inherently unstable, but less susceptible to upset by gusty sidewinds.

In July 1899 Wilbur put wing warping to the test by building and flying a five-foot box kite in the approximate shape of a biplane. When the wings were warped, or twisted, one end would receive more lift and rise, starting a turn in the direction of the lower end. Warping was controlled by four lines attached to the kite. The lines led to two sticks held by the kite flyer, who tilted them in opposite directions to twist the wings and make the kite bank left or right.

In 1900 the brothers journeyed to Kitty Hawk, North Carolina, to begin their manned gliding experiments. Wilbur chose the location on the basis of a reply to his first letter to Octave Chanute, whose suggestions included the Atlantic coast for regular breezes and a soft sandy landing surface. Wilbur also requested and scrutinized U.S. Weather Bureau data, and selected Kitty Hawk after writing to the government meteorologist stationed there. The location, although remote, was closer to Dayton than other places Chanute had suggested, including California and Florida. The spot also gave them privacy from reporters, who had turned the 1896 Chanute experiments at Lake Michigan into something of a circus. Chanute visited them in camp each season from 1901 to 1903 and saw gliding experiments, but not the powered flights. The Wrights based the design of their first full-size glider (as well as the 1899 kite) on the work of their recent predecessors, chiefly the Chanute-Herring biplane hang glider ("double-decker", as the Wrights called it), which flew well in the 1896 experiments near Chicago; and aeronautical data on lift that Lilienthal had published. The Wrights designed the wings with camber, a curvature of the top surface. The brothers did not discover this principle, but took advantage of it. The better lift of a cambered surface compared to a flat one was first discussed scientifically by Sir George Cayley. Lilienthal, whose work the Wrights carefully studied, used cambered wings in his gliders, proving in flight the advantage over flat surfaces. The wooden uprights between the wings of the Wright glider were braced by wires in their own adaptation of Chanute's modified "Pratt truss", a bridge-building design he used in his 1896 glider. The Wrights mounted the horizontal elevator in front of the wings rather than behind, apparently believing this feature would help avoid a nosedive and crash like the one that killed Lilienthal. (Later, when Brazilian aviation pioneer Santos-Dumont, flew his 14-bis in Paris in 1906, French newspapers dubbed the tail-first arrangement a "canard", because of the supposed resemblance to a duck in flight.) Wilbur incorrectly believed a tail was not necessary, and their first two gliders did not have one. According to some Wright biographers, Wilbur probably did all the gliding until 1902, perhaps to exercise his authority as older brother and to protect Orville from harm. The brothers flew the glider only a few days in the early autumn of 1900 at Kitty Hawk. In the first tests, probably October 3, Wilbur was aboard while the glider flew as a kite not far above the ground with men below holding tether ropes. Most of the kite tests were unpiloted with sandbags or chains (and even a local boy) as onboard ballast.

They tested wing-warping using control ropes from the ground. The glider was also tested unmanned while suspended from a small homemade tower. Wilbur (but not Orville) made about a dozen free glides on only a single day. For those tests, the brothers trekked four miles (6 km) south to the Kill Devil Hills, a group of sand dunes up to 100 feet (30 m) high (where they made camp in each of the next three years). Although the glider's lift was less than expected (causing most tests to be unmanned), the brothers were encouraged because the craft's front elevator worked well and they had no accidents. However, the small number of free glides meant they were not able to give wing-warping a true test. The pilot lay flat on the lower wing, as planned, to reduce aerodynamic drag. As a glide ended, the pilot was supposed to lower himself to a vertical position through an opening in the wing and land on his feet with his arms wrapped over the framework. Within a few glides, however, they discovered the pilot could remain prone on the wing, headfirst, without undue danger when landing. They made all their flights in that position for the next five years.

Hoping to improve lift, they built the 1901 glider with a much larger wing area and made 50 to 100 flights in July and August for distances of 20 to 400 ft (6 to 122 m). The glider stalled a few times, but the parachute effect of the forward elevator allowed Wilbur to make a safe flat or "pancake" landing, instead of a nose-dive. These incidents wedded the Wrights even more strongly to the canard design, which they did not give up until 1910. The glider, however, delivered two major disappointments. It produced only about one-third the lift calculated and sometimes failed to respond properly to wing-warping, turning opposite the direction intended — a problem later known as adverse yaw. On the trip home after their second season, Wilbur, stung with disappointment, remarked to Orville that man would fly, but not in their lifetimes. The poor lift of the gliders led the Wrights to question the accuracy of Lilienthal's data, as well as the "Smeaton coefficient" of air pressure, which had been in existence for over 100 years and was part of the accepted equation for lift. The Wrights — and Lilienthal — used the equation to calculate the amount of lift that wings of various sizes would produce. On the basis of measurements of lift and wind during the 1901 glider's kite and free flights, Wilbur believed (correctly, as tests later showed) that the Smeaton number was very close to 0.0033, not the traditionally used 60 percent larger 0.0054, which would exaggerate predicted lift.

Back home, furiously pedaling a strange-looking bicycle on neighborhood streets, they conducted makeshift open-air tests with a miniature Lilienthal airfoil and a counter-acting flat plate, which were both attached to a freely rotating third bicycle wheel mounted horizontally in front of the handlebars. Because the third wheel rotated against the airfoil instead of remaining motionless as the calculations predicted, the Wrights confirmed their suspicion that published data on lift were unreliable, and they decided to expand their investigation. They also realized that trial-and-error with different wings on full-size gliders was too costly and time-consuming. Putting aside the three-wheel bicycle, they built a six-foot wind tunnel in their shop and conducted systematic tests on miniature wings from October to December 1901. The "balances" they devised and mounted inside the tunnel to hold the wings looked crude, made of bicycle spokes and scrap metal, but were "as critical to the ultimate success of the Wright brothers as were the gliders." The devices allowed the brothers to balance lift against drag and accurately calculate the performance of each wing. They could also see which wings worked well as they looked through the viewing window in the top of the tunnel. Prior to beginning their wind tunnel experiments, Wilbur, at Chanute's invitation, traveled to Chicago to give a speech to the Western Society of Engineers on September 18, 1901. Wilbur's speech consisted of detailed accounts of his and Orville's glider experiments at Kitty Hawk up to the fall of 1901 and was complemented by a lantern slide show of photographs. Wilbur's speech was the first public account of the brothers' experiments. Lilienthal had made "whirling arm" tests on only a few wing shapes, and the Wrights mistakenly assumed the data would apply to their wings, which had a different shape. The Wrights took a huge step forward and made basic wind tunnel tests on 200 wings of many shapes and airfoil curves, followed by detailed tests on 38 of them. The tests, according to biographer Howard, "were the most crucial and fruitful aeronautical experiments ever conducted in so short a time with so few materials and at so little expense". An important discovery was the benefit of longer narrower wings: in aeronautical terms, wings with a larger aspect ratio (wingspan divided by chord — the wing's front-to-back dimension). Such shapes offered much better lift-to-drag ratio than the broader wings the brothers had tried so far.

With this knowledge, and a more accurate Smeaton number, the Wrights designed their 1902 glider. Using another crucial discovery from the wind tunnel, they made the airfoil flatter, reducing the camber (the depth of the wing's curvature divided by its chord). The 1901 wings had significantly greater curvature, a highly inefficient feature the Wrights copied directly from Lilienthal. Fully confident in their new wind tunnel results, the Wrights discarded Lilienthal's data, now basing their designs on their own calculations. With characteristic caution, the brothers first flew the 1902 glider as an unmanned kite, as they had done with their two previous versions. Rewarding their wind tunnel work, the glider produced the expected lift. It also had a new structural feature: a fixed, rear vertical rudder, which the brothers hoped would eliminate turning problems. By 1902 they realized that wing-warping created "differential drag" at the wingtips. Greater lift at one end of the wing also increased drag, which slowed that end of the wing, making the aircraft swivel — or "yaw" — so the nose pointed away from the turn. That was how the tailless 1901 glider behaved. The improved wing design enabled consistently longer glides, and the rear rudder prevented adverse yaw — so effectively that it introduced a new problem. Sometimes when the pilot attempted to level off from a turn, the glider failed to respond to corrective wing-warping and persisted into a tighter turn. The glider would slide toward the lower wing, which hit the ground, spinning the aircraft around. The Wrights called this "well digging".

Orville apparently visualized that the fixed rudder resisted the effect of corrective wing-warping when attempting to level off from a turn. He wrote in his diary that on the night of October 2, "I studied out a new vertical rudder". The brothers then decided to make the rear rudder movable to solve the problem. They hinged the rudder and connected it to the pilot's warping "cradle", so a single movement by the pilot simultaneously controlled wing-warping and rudder deflection. Tests while gliding proved that the trailing edge of the rudder should be turned away from whichever end of the wings had more drag (and lift) due to warping. The opposing pressure produced by turning the rudder enabled corrective wing-warping to reliably restore level flight after a turn or a wind disturbance. Furthermore, when the glider banked into a turn, rudder pressure overcame the effect of differential drag and pointed the nose of the aircraft in the direction of the turn, eliminating adverse yaw. In short, the Wrights discovered the true purpose of the movable vertical rudder. Its role was not to change the direction of flight, but rather, to aim or align the aircraft correctly during banking turns and when leveling off from turns and wind disturbances. The actual turn — the change in direction — was done with roll control using wing-warping. The principles remained the same when ailerons superseded wing-warping. With their new method the Wrights achieved true control in turns for the first time on October 8, 1902, a major milestone. During September and October they made between 700 and 1,000 glides, the longest lasting 26 seconds and covering 622.5 feet (189.7 m). Hundreds of well-controlled glides after they made the rudder steerable convinced them they were ready to build a powered flying machine.

Thus did three-axis control evolve: wing-warping for roll (lateral motion), forward elevator for pitch (up and down) and rear rudder for yaw (side to side). On March 23, 1903, the Wrights applied for their famous patent for a "Flying Machine", based on their successful 1902 glider. Some aviation historians believe that applying the system of three-axis flight control on the 1902 glider was equal to, or even more significant, than the addition of power to the 1903 Flyer. Peter Jakab of the Smithsonian asserts that perfection of the 1902 glider essentially represents invention of the airplane. In 1903 the brothers built the powered Wright Flyer I, using their preferred material for construction, spruce, a strong and lightweight wood, and Pride of the West muslin for surface coverings. They also designed and carved their own wooden propellers, and had a purpose-built gasoline engine fabricated in their bicycle shop. They thought propeller design would be a simple matter and intended to adapt data from shipbuilding. However, their library research disclosed no established formulas for either marine or air propellers, and they found themselves with no sure starting point. They discussed and argued the question, sometimes heatedly, until they concluded that an aeronautical propeller is essentially a wing rotating in the vertical plane. On that basis, they used data from more wind tunnel tests to design their propellers. The finished blades were just over eight feet long, made of three laminations of glued spruce. The Wrights decided on twin "pusher" propellers (counter-rotating to cancel torque), which would act on a greater quantity of air than a single relatively slow propeller and not disturb airflow over the leading edge of the wings.

Wilbur made a March 1903 entry in his notebook indicating the prototype propeller was 66% efficient. Modern wind tunnel tests on reproduction 1903 propellers show they were more than 75% efficient under the conditions of the first flights, and actually had a peak efficiency of 82%. This is a remarkable achievement, considering that modern wooden propellers have a maximum efficiency of 85%. The Wrights wrote to several engine manufacturers, but none met their need for a sufficiently lightweight powerplant. They turned to their shop mechanic, Charlie Taylor, who built an engine in just six weeks in close consultation with the brothers. To keep the weight low enough, the engine block was cast from aluminum, a rare practice for the time. The Wright/Taylor engine was a primitive version of modern fuel-injection systems, having no carburetor or fuel pump. Gasoline was gravity-fed into the crankcase through a rubber tube from the fuel tank mounted on a wing strut. The propeller drive chains, resembling those of bicycles, were actually supplied by a manufacturer of heavy-duty automobile chain-drives. The Flyer cost less than a thousand dollars, in contrast to more than $50,000 in government funds given to Samuel Langley for his man-carrying Great Aerodrome. The Flyer had a wingspan of 40.3 ft (12.3 m), weighed 605 lb (274 kg) and sported a 12 horsepower (8.9 kW) 180 lb (82 kg) engine.

In camp at Kill Devil Hills, they suffered weeks of delays caused by broken propeller shafts during engine tests. After the shafts were replaced (requiring two trips back to Dayton), Wilbur won a coin toss and made a three-second flight attempt on December 14, 1903, stalling after takeoff and causing minor damage to the Flyer. (Because December 13, 1903, was a Sunday, the brothers did not make any attempts that day, even though the weather was good.) In a message to their family, Wilbur referred to the trial as having "only partial success", stating "the power is ample, and but for a trifling error due to lack of experience with this machine and this method of starting, the machine would undoubtedly have flown beautifully." Following repairs, the Wrights finally took to the air on December 17, 1903, making two flights each from level ground into a freezing headwind gusting to 27 miles per hour (43 km/h). The first flight, by Orville, of 120 feet (37 m) in 12 seconds, at a speed of only 6.8 miles per hour (10.9 km/h) over the ground, was recorded in a famous photograph. The next two flights covered approximately 175 feet (53 m) and 200 feet (61 m), by Wilbur and Orville respectively. Their altitude was about 10 feet (3.0 m) above the ground. Five people witnessed the flights: Adam Etheridge, John Daniels (who snapped the famous "first flight" photo using Orville's pre-positioned camera) and Will Dough, all of the U.S. government coastal lifesaving crew; area businessman W.C. Brinkley; and Johnny Moore, a teenaged boy who lived in the area. After the men hauled the Flyer back from its fourth flight, a powerful gust of wind flipped it over several times, despite the crew's attempt to hold it down. Severely damaged, the airplane never flew again. The brothers shipped it home, and years later Orville restored it, lending it to several U.S. locations for display, then to a British museum, before it was finally installed in the Smithsonian Institution in Washington, D.C., in 1948, its current residence.

The Wrights sent a telegram about the flights to their father, requesting that he "inform press." However, the Dayton Journal refused to publish the story, saying the flights were too short to be important. Meanwhile, against the brothers' wishes, a telegraph operator leaked their message to a Virginia newspaper, which concocted a highly inaccurate news article that was reprinted the next day in several newspapers elsewhere, including Dayton. The Wrights issued their own factual statement to the press in January. Nevertheless, the flights did not create public excitement — if people even knew about them — and the news soon faded. (In Paris, however, Aero Club of France members, already stimulated by Chanute's reports of Wright gliding successes, took the news more seriously and increased their efforts to catch up to the brothers.)

In 1904 the Wrights built the Flyer II. They decided to avoid the expense of travel and bringing supplies to the Outer Banks and set up an airfield at Huffman Prairie, a cow pasture eight miles (13 km) northeast of Dayton. They received permission to use the field rent-free from owner and bank president Torrance Huffman. They invited reporters to their first flight attempt of the year on May 23, on the condition that no photographs be taken. Engine troubles and slack winds prevented any flying, and they could manage only a very short hop a few days later with fewer reporters present. Some scholars of the Wrights speculate the brothers may have intentionally failed to fly in order to disinterest reporters in their experiments. Whether that is true is not known, but after their poor showing local newspapers virtually ignored them for the next year and a half. The Wrights were glad to be free from the distraction of reporters. The absence of newsmen also reduced the chance of competitors learning their methods. After the Kitty Hawk powered flights, the Wrights made a decision to begin withdrawing from the bicycle business so they could devote themselves to creating and marketing a practical airplane. The decision was financially risky, since they were neither wealthy nor government-funded (unlike other experimenters such as Ader, Maxim, Langley and Santos-Dumont). The Wright brothers did not have the luxury of giving away their invention; it was to be their livelihood. Thus, their secrecy intensified, encouraged by advice from their patent attorney, Henry Toulmin, not to reveal details of their machine.
At Huffman Prairie, lighter winds and lower air density than in Kitty Hawk (because of Ohio's higher altitude and higher temperatures) made takeoffs very difficult, and they had to use a much longer starting rail, stretching to hundreds of feet, compared to the 60-foot (18 m) rail at Kitty Hawk. During the spring and summer they suffered many hard landings, real crackups, repeated Flyer damage, and bodily bumps and bruises. On August 13, making an unassisted takeoff, Wilbur finally exceeded their best Kitty Hawk effort with a flight of 1,300 feet (400 m). Then they decided to use a weight-powered catapult to make takeoffs easier and tried it for the first time on September 7. On September 20, 1904, Wilbur flew the first complete circle in history by a manned heavier-than-air powered machine, covering 4,080 feet (1,244 m) in about a minute and a half. Their two best flights were November 9 by Wilbur and December 1 by Orville, each exceeding five minutes and covering nearly three miles in almost four circles. By the end of the year the brothers had accumulated about 50 minutes in the air in 105 flights over the rather soggy 85 acre pasture, which, remarkably, is virtually unchanged today from its original condition and is now part of Dayton Aviation Heritage National Historical Park, adjacent to Wright-Patterson Air Force Base.

Despite progress in 1904, the Flyer was still frequently out of control. The Wrights scrapped the battered and much-repaired airplane, but saved the engine, and in 1905 built a new Flyer III, which included an important design change. The brothers installed a separate control for the rear rudder instead of linking the rudder to the wing-warping "cradle" as before. Each of the three axes — pitch, roll and yaw — now had its own independent control. Nevertheless, this Flyer offered the same marginal performance as the first two. Its maiden flight was June 23 and the first several flights were no longer than 10 seconds. After Orville suffered a bone-jarring and potentially fatal crash on July 14, they rebuilt the Flyer with the forward elevator and rear rudder both enlarged and placed several feet farther away from the wings. These modifications greatly improved stability and control, setting the stage for a series of six dramatic "long flights" ranging from 17 to 38 minutes and 11 to 24 miles (39 km) around the three-quarter mile course over Huffman Prairie between September 26 and October 5. Wilbur made the last and longest flight, 24.5 miles (39.4 km) in 38 minutes and 3 seconds, ending with a safe landing when the fuel ran out. The flight was seen by a number of people, including several invited friends, their father Milton, and neighboring farmers. Reporters showed up the next day (only their second appearance at the field since May the previous year), but the brothers declined to fly. The long flights convinced the Wrights they had achieved their goal of creating a flying machine of "practical utility" which they could offer to sell.

The only photos of the flights of 1904–1905 were taken by the brothers. (A few photos were damaged in the Great Dayton Flood of 1913, but most survived intact.) In 1904 Ohio beekeeping businessman Amos Root, a technology enthusiast, saw a few flights including the first circle. Articles he wrote for his beekeeping magazine were the only published eyewitness reports of the Huffman Prairie flights, except for the unimpressive early hop local newsmen saw. Root offered a report to Scientific American magazine, but the editor turned it down. As a result, the news was not widely known outside of Ohio, and was often met with skepticism. The Paris edition of the Herald Tribune headlined a 1906 article on the Wrights "FLYERS OR LIARS?" In years to come Dayton newspapers would proudly celebrate the hometown Wright brothers as national heroes, but the local reporters somehow missed one of the most important stories in history as it was happening a few miles from their doorstep. James M. Cox, publisher at that time of the Dayton Daily News (later governor of Ohio and Democratic presidential nominee in 1920), expressed the attitude of newspapermen — and the public — in those days when he admitted years later, "Frankly, none of us believed it." A few newspapers published articles about the long flights, but no reporters or photographers had been there. The lack of splashy eyewitness press coverage was a major reason for disbelief in Washington, D.C., and Europe and in journals like Scientific American, whose editors doubted the "alleged experiments" and asked how U.S. newspapers, "alert as they are, allowed these sensational performances to escape their notice."

The Wright brothers were certainly complicit in the lack of attention they received. Fearful of competitors stealing their ideas, and still without a patent, they flew on only one more day after October 5. From then on, they refused to fly anywhere unless they had a firm contract to sell their aircraft. They wrote to the U.S. government, then to Britain, France and Germany with an offer to sell a flying machine, but were rebuffed because they insisted on a signed contract before giving a demonstration. They were unwilling even to show their photographs of the airborne Flyer. The American military, having recently spent $50,000 on the Langley Aerodrome — a product of the nation's foremost scientist — only to see it plunge twice into the Potomac River "like a handful of mortar", was particularly unreceptive to the claims of two unknown bicycle makers from Ohio. Thus, doubted or scorned, the Wright brothers continued their work in semi-obscurity, while other aviation pioneers like Brazilian Alberto Santos-Dumont and American Glenn Curtiss entered the limelight.

In 1906, skeptics in the European aviation community had converted the press to an anti-Wright brothers stance. European newspapers, especially in France, were openly derisive, calling them bluffeurs (bluffers). Ernest Archdeacon, founder of the Aéro-Club de France, was publicly scornful of the brother's claims in spite of published reports; specifically, he wrote several articles and in 1906, stated that the French would make the first public demonstration of powered flight. The Paris edition of the New York Herald summed up Europe's opinion of the Wright brothers in an editorial on February 10, 1906:

"The Wrights have flown or they have not flown. They possess a machine or they do not possess one. They are in fact either fliers or liars. It is difficult to fly. It's easy to say, 'We have flown.'"

The Alberto Santos-Dumont´s public flight, in 1906, is the first to have been certified by the Aéro Club de France and the Fédération Aéronautique Internationale (FAI). In 1908, after the Wrights' first flights in France, Archdeacon publicly admitted that he had done them an injustice.

The Wright brothers made no flights at all in 1906 and 1907 while they pursued fitful negotiations with the U.S. and European governments. While grounded they experimented with a pontoon and engine setup on the Miami River in hopes of flying their airplane from the water. These experiments proved unsuccessful. In May 1906 they were finally granted a patent for their flying machine. In 1907 the brothers journeyed to Europe for the first time for face-to-face talks with government bureaucrats and businessmen. Orville joined his brother two months after Wilbur's departure, but first packed a new Model A Flyer in a crate which was shipped to France and left in storage at Le Havre in anticipation of demonstration flights. In early 1908 the Wrights finally signed contracts with a French company and the U.S. Army. In May they went back to Kitty Hawk with their 1905 Flyer to practice for their all-important demonstration flights. They had not been to the camp in four and a half years and had to rebuild their two sheds, which had been badly damaged by weather and scavengers; the 1902 glider was in a hopeless state of disrepair.

Their American and French contracts required them to be able to carry a passenger. They modified the 1905 Flyer by installing two seats and adding upright control levers. After tests with sandbags in the passenger seat, Charlie Furnas, a helper from Dayton, became the first fixed-wing aircraft passenger on a few short flights May 14. For safety, and as a promise to their father, Wilbur and Orville did not fly together. However, several newspaper accounts at the time mistakenly took Orville's flight with Furnas as both brothers flying together. Later that day after flying solo seven minutes, Wilbur suffered his worst crash when, still not well-acquainted with the two control levers, he apparently moved one the wrong way and slammed the Flyer into the sand between 40 and 50 miles an hour. He emerged with only bruises and a cut nose, but the accident ended the practice flights — and the airplane's flying career.

The brothers' contracts with the U.S. Army and a French syndicate depended on successful public flight demonstrations that met certain conditions. The brothers had to divide their efforts. Wilbur sailed for Europe; Orville would fly near Washington, D.C. Wilbur faced deep skepticism in the French aeronautical community and outright scorn by some newspapers that called him a "bluffeur", but he began official public demonstrations on August 8, 1908 at the Hunaudières horse racing track near the town of Le Mans, France. His first flight lasted only one minute 45 seconds, but his ability to effortlessly make banking turns and fly a circle amazed and stunned onlookers, including several pioneer French aviators, among them Louis Bleriot. In the following days, Wilbur made a series of technically challenging flights, including figure-eights, demonstrating his skills as a pilot and the capability of his flying machine, which far surpassed those of all other pilot pioneers. The French public was thrilled by Wilbur's feats and flocked to the field by the thousands. The Wright brothers catapulted to world fame overnight. Former doubters issued apologies and effusive praise. "L'Aérophile" editor Georges Besançon wrote that the flights "have completely dissipated all doubts. Not one of the former detractors of the Wrights dare question, today, the previous experiments of the men who were truly the first to fly...." Leading French aviation promoter Ernest Archdeacon wrote, "For a long time, the Wright brothers have been accused in Europe of bluff... They are today hallowed in France, and I feel an intense pleasure...to make amends." On October 7, 1908, Edith Berg, the wife of the brothers' European business agent, became the first American woman airplane passenger when she flew with Wilbur —- one of many passengers who rode with him that autumn.

Orville followed his brother's success by demonstrating another nearly identical flyer to the United States Army at Fort Myer, Virginia, starting on September 3, 1908. On September 9, he made the first hour-long flight, lasting 62 minutes and 15 seconds. On September 17, Army lieutenant Thomas Selfridge rode along as his passenger, serving as an official observer. A few minutes into the flight at an altitude of about 100 feet (30 m), a propeller split and shattered, sending the aircraft out of control. Selfridge suffered a fractured skull in the crash and died that evening in the nearby Army hospital, becoming the first fatality of an airplane crash. Orville was badly injured, suffering a broken left leg and four broken ribs. Twelve years later, after he suffered increasingly severe pains, X-rays revealed the accident had also caused three hip bone fractures and a dislocated hip. The brothers' sister Katharine, a school teacher, rushed from Dayton to Virginia and stayed by Orville's side for the seven weeks of his hospitalization. She helped negotiate a one-year extension of the Army contract. A friend visiting Orville in the hospital asked, "Has it got your nerve?" "Nerve?" repeated Orville, slightly puzzled. "Oh, do you mean will I be afraid to fly again? The only thing I'm afraid of is that I can't get well soon enough to finish those tests next year." Deeply shocked by the accident, Wilbur determined to make even more impressive flight demonstrations; in the ensuing days and weeks he set new records for altitude and duration. In January 1909 Orville and Katharine joined him in France, and for a time they were the three most famous people in the world, sought after by royalty, the rich, reporters and the public. The kings of England, Spain and Italy came to see Wilbur fly. The Wrights traveled to Pau, in the south of France, where Wilbur made many more public flights, giving rides to a procession of officers, journalists and statesmen — and his sister Katharine on February 15. He trained two French pilots, then transferred the airplane to the French company. In April the Wrights went to Italy where Wilbur assembled another Flyer, giving demonstrations and training more pilots. A cameraman climbed aboard and made the first motion picture from an airplane.

After their return to the U.S., the brothers and Katharine were invited to the White House where President Taft bestowed awards upon them. Dayton followed up with a lavish two-day homecoming celebration. In July 1909 Orville, with Wilbur assisting, completed the proving flights for the U.S. Army, meeting the requirements of a two-seater able to fly with a passenger for an hour at an average speed of 40 miles an hour (64 km/h) and land undamaged. They sold the aircraft to the Army's Aeronautical Division, U.S. Signal Corps for $30,000 (which included a $5,000 bonus for exceeding the speed specification). Wilbur climaxed an extraordinary year in early October when he flew at New York City's Hudson-Fulton celebrations, circling the Statue of Liberty and making a 33-minute flight up and down the Hudson River alongside Manhattan in view of up to one million New Yorkers. These flights solidly established the fame of the Wright brothers in America.

On May 25, 1910 back at Huffman Prairie, Orville piloted two unique flights. First, he took off on a six-minute flight with Wilbur as his passenger, the only time the Wright brothers ever flew together. They received permission from their father to make the flight. They had always promised Milton they would never fly together to avoid the chance of a double tragedy and to ensure one brother would remain to continue their experiments. Next, Orville took his 82-year old father on a nearly seven-minute flight, the first and only one of Milton Wright's life. The airplane rose to about 350 feet (107 m) while the elderly Wright called to his son, "Higher, Orville, higher!"

The Wright brothers wrote their 1903 patent application themselves, but it was rejected. In January 1904 they hired Ohio patent attorney Henry Toulmin, and on May 22, 1906, they were granted U.S. Patent 821393 for a "Flying Machine". The patent illustrates a non-powered flying machine — namely, the 1902 glider. The patent's importance lies in its claim of a new and useful method of controlling a flying machine, powered or not. The technique of wing-warping is described, but the patent explicitly states that other methods instead of wing-warping could be used for adjusting the outer portions of a machine's wings to different angles on the right and left sides to achieve lateral (roll) control. The concept of varying the angle presented to the air near the wingtips, by any suitable method, is central to the patent. The patent also describes the steerable rear vertical rudder and its innovative use in combination with wing-warping, enabling the airplane to make a coordinated turn, a technique that prevents hazardous adverse yaw, the problem Wilbur had when trying to turn the 1901 glider. Finally, the patent describes the forward elevator, used for ascending and descending.

Attempting to circumvent the patent, Glenn Curtiss and other early aviators devised ailerons to emulate lateral control described in the patent and demonstrated by the Wrights in their public flights. Soon after the historic July 4, 1908 one-kilometer flight by Curtiss in the June Bug, the Wrights warned him not to infringe their patent by profiting from flying or selling aircraft that used ailerons. Curtiss refused to pay license fees to the Wrights and sold an airplane equipped with ailerons to the Aeronautic Society of New York in 1909. The Wrights filed a lawsuit, beginning a years-long legal conflict. They also sued foreign aviators who flew at U.S. exhibitions, including the leading French aviator Louis Paulhan. The Curtiss people derisively suggested that if someone jumped in the air and waved his arms, the Wrights would sue. European companies which bought foreign patents the Wrights had received sued other manufacturers in their countries. Those lawsuits were only partly successful. Despite a pro-Wright ruling in France, legal maneuvering dragged on until the patent expired in 1917. A German court ruled the patent not valid because of prior disclosure in speeches by Wilbur Wright in 1901 and Octave Chanute in 1903. In the U.S. the Wrights made an agreement with the Aero Club of America to license airshows which the Club approved, freeing participating pilots from a legal threat. Promoters of approved shows paid fees to the Wrights. The Wright brothers won their initial case against Curtiss in February 1913, but the decision was appealed. From 1910 until his death from typhoid fever in 1912, Wilbur took the leading role in the patent struggle, traveling incessantly to consult with lawyers and testify in what he felt was a moral cause, particularly against Curtiss, who was creating a large company to manufacture aircraft. The Wrights' preoccupation with the legal issue stifled their work on new designs, and by 1911 Wright aircraft were considered inferior to those of European makers. Indeed, aviation development in the U.S. was suppressed to such an extent that when the U.S. entered World War I no acceptable American-designed aircraft were available, and U.S. forces were compelled to use French machines. Orville and Katharine Wright believed Curtiss was partly responsible for Wilbur's premature death, which occurred in the wake of his exhausting travels and the stress of the legal battle. In January 1914, a U.S. Circuit Court of Appeals upheld the verdict against the Curtiss company, which continued to avoid penalties through legal tactics. Orville apparently felt vindicated by the decision, and much to the frustration of company executives, he did not push vigorously for further legal action to ensure a manufacturing monopoly. In fact, he was planning to sell the company and departed in 1915. In 1917, with World War I underway, the U.S. government pressured the industry to form a cross-licensing organization, the Manufacturers Aircraft Association, to which member companies paid a blanket fee for the use of aviation patents, including the original and subsequent Wright patents. The Wright-Martin company (successor to the Wright company) and the Curtiss company (which held a number of its own patents) each received a $2 million payment. The "patent war" ended, although side issues lingered in the courts until the 1920s. In a twist of irony, the Wright Aeronautical Corporation (another successor) and the Curtiss Aeroplane company merged in 1929 to form the Curtiss-Wright corporation, which remains in business today producing high-tech components for the aerospace industry.

The lawsuits damaged the public image of the Wright brothers, who were generally regarded before this as heroes. Critics said the brothers were greedy and unfair and compared their actions unfavorably to European inventors, who worked more openly. Supporters said the brothers were protecting their interests and were justified in expecting fair compensation for the years of work leading to their successful invention. Their ten-year friendship with Octave Chanute, already strained by tension over how much credit, if any, he might deserve for their success, collapsed after he publicly criticized their actions. The Wright Company was incorporated on November 22, 1909. The brothers sold their patents to the company for $100,000 and also received one-third of the shares in a million dollar stock issue and a 10 percent royalty on every airplane sold. With Wilbur as president and Orville as vice president, the company set up an airplane factory in Dayton and a flying school/test flight field at Huffman Prairie; the headquarters office was in New York City. In mid-1910 the Wrights changed the design of their airplane, moving the horizontal elevator from the front to the back and adding wheels. It had become apparent by then that a rear elevator would make the airplane easier to control, especially as higher speeds grew more common. This aircraft was designated the "Model B", although the original canard design was never referred to as the "Model A" by the Wrights. However, the US Signal Corps which bought the airplane did call it "Wright Type A". There were not many customers for aircraft, so in the spring of 1910 the Wrights hired and trained a team of salaried exhibition pilots to show off their machines and win prize money for the company — despite Wilbur's disdain for what he called "the mountebank business". The team debuted at the Indianapolis Speedway on June 13. Before the year was over, pilots Ralph Johnstone and Arch Hoxsey died in air show crashes, and in November 1911 the brothers disbanded the team on which nine men had served (four other former team members died in crashes afterward).

The Wright Company transported the first known commercial air cargo on November 7, 1910 by flying two bolts of dress silk 65 miles (105 km) from Dayton to Columbus, Ohio for the Moorehouse-Marten Department Store, which paid a $5,000 fee. Company pilot Phil Parmelee made the flight — which was more an exercise in advertising than a simple delivery — in an hour and six minutes with the cargo strapped in the passenger's seat. The silk was cut into small pieces and sold as souvenirs. Between 1910 and 1916 the Wright Company flying school at Huffman Prairie trained 115 pilots who were instructed by Orville and his assistants. Several trainees became famous, including Henry "Hap" Arnold, who rose to Five-Star General, commanded U.S. Army Air Forces in World War II, and became first head of the U.S. Air Force; Calbraith Perry Rodgers, who made the first coast-to-coast flight in 1911 (with many stops and crashes) in a Wright Model EX named the "Vin Fiz" after the sponsor's soft drink; and Eddie Stinson, founder of the Stinson Aircraft Company.

Samuel P. Langley, secretary of the Smithsonian Institution from 1887 until his death in 1906, experimented for years with model flying machines and successfully flew unmanned powered model aircraft in 1896 and 1903. Two tests of his manned full-size motor-driven Aerodrome in October and December 1903, however, were complete failures. Nevertheless, the Smithsonian later proudly displayed the Aerodrome in its museum as the first heavier-than-air craft "capable" of manned powered flight, relegating the Wright brothers' invention to secondary status and ironically triggering a decades-long feud with Orville Wright, whose brother had received help from the Smithsonian when beginning his own quest for flight. The Smithsonian based its claim for the Aerodrome on short test flights Glenn Curtiss and his team made with it in 1914. The Smithsonian allowed Curtiss, in an unsavory alliance, to make major modifications to the craft before attempting to fly it. The Smithsonian hoped to salvage Langley's aeronautical reputation by proving the Aerodrome could fly; Curtiss wanted to prove the same thing to defeat the Wrights' patent lawsuits against him. The tests had no effect on the patent battle, but the Smithsonian made the most of them, honoring the Aerodrome in its museum and publications. The Institution did not reveal the extensive Curtiss modifications, but Orville Wright learned of them from his brother Lorin and a close friend, Griffith Brewer, who both witnessed and photographed some of the tests. Orville repeatedly objected to misrepresentation of the Aerodrome, but the Smithsonian was unyielding. Orville responded by loaning the restored 1903 Kitty Hawk Flyer to the London Science Museum in 1928, refusing to donate it to the Smithsonian while the Institution "perverted" the history of the flying machine. Subsequently Orville would never see his airplane again as he would die before its return to the United States. Charles Lindbergh attempted to mediate the dispute, to no avail. In 1942, after years of bad publicity, and encouraged by Wright biographer Fred C. Kelly, the Smithsonian finally relented by publishing, for the first time, a list of the Aerodrome modifications and recanting misleading statements it had made about the 1914 tests. Orville then privately requested the British museum to return the Flyer, but the airplane remained in protective storage for the duration of World War II and finally came home after Orville's death.

On November 23, 1948, the executors of Orville's estate signed an agreement for the Smithsonian to purchase the Flyer for one dollar. At the insistence of the executors, the agreement also included strict conditions for display of the airplane. The agreement reads, in part, "Neither the Smithsonian Institution or its successors, nor any museum or other agency, bureau or facilities administered for the United States of America by the Smithsonian Institution or its successors shall publish or permit to be displayed a statement or label in connection with or in respect of any aircraft model or design of earlier date than the 1903 Wright Aeroplane, claiming in effect that such aircraft was capable of carrying a man under its own power in controlled flight." If this agreement is not fulfilled, the Flyer can be reclaimed by the heir of the Wright brothers. Some aviation buffs, particularly those who promote the legacy of Gustave Whitehead, now accuse the Smithsonian of refusing to investigate claims of earlier flights. After a ceremony in the Smithsonian museum, the Flyer went on public display on December 17, 1948, the 45th anniversary of the only day it was flown successfully. The Wright brothers' nephew Milton (Lorin's son), who had seen gliders and the Flyer under construction in the bicycle shop when he was a boy, gave a brief speech and formally transferred the airplane to the Smithsonian.

Neither brother married. Wilbur once quipped that he did not have time for both a wife and an airplane. He became ill on a trip to Boston in April 1912. After returning to Dayton, he was diagnosed with typhoid fever. He died, at age 45, in the Wright family home on May 30. His father Milton wrote about Wilbur in his diary: "A short life, full of consequences. An unfailing intellect, imperturbable temper, great self-reliance and as great modesty, seeing the right clearly, pursuing it steadfastly, he lived and died."

Orville succeeded to the presidency of the Wright company upon Wilbur's death. Sharing Wilbur's distaste for business but not his brother's executive skills, Orville sold the company in 1915. He, Katharine and their father Milton moved to a mansion, Hawthorn Hill, Oakwood, Ohio, which the newly wealthy family built. Milton died in his sleep in 1917. Orville made his last flight as a pilot in 1918. He retired from business and became an elder statesman of aviation, serving on various official boards and committees, including the National Advisory Committee for Aeronautics (NACA), predecessor agency to the National Aeronautics and Space Administration (NASA) and Aeronautical Chamber of Commerce (ACCA), predecessor to the Aerospace Industries Association (AIA). Katharine married Henry Haskell of Kansas City, a former Oberlin classmate, in 1926, which greatly upset Orville. He refused to attend the wedding or even communicate with her. He finally agreed to see her, apparently at Lorin's insistence, just before she died of pneumonia in 1929. Orville Wright served NACA for 28 years. In 1930, he received the first Daniel Guggenheim Medal established in 1928 by the Daniel Guggenheim Fund for the Promotion of Aeronautics. In 1936, he was elected a member of the National Academy of Sciences.

On April 19, 1944, the second production Lockheed Constellation, piloted by Howard Hughesand TWA president Jack Frye, flew from Burbank, California, to Washington, D.C., in 6 hours and 57 minutes. On the return trip, the aircraft stopped at Wright Field to give Orville Wright his last airplane flight, more than 40 years after his historic first flight. He may even have briefly handled the controls. He commented that the wingspan of the Constellation was longer than the distance of his first flight.

Orville died in 1948 after his second heart attack, having lived from the horse-and-buggy age to the dawn of supersonic flight. Both brothers are buried at the family plot at Woodland Cemetery, Dayton, Ohio.

First flight claims are made for Ader, Whitehead, Pearse and Jatho for their variously documented tests in years prior to and including 1903. Claims that the first true flight occurred after 1903 are made for Vuia and Santos-Dumont. Supporters of these pre- and post-Wright pioneers argue that techniques used by the Wright brothers disqualify them as first to make successful airplane flights. Those techniques were: a launch rail; skids instead of wheels; a headwind at takeoff; and a catapult after 1903. Supporters of the Wright brothers argue that proven, repeated, controlled and sustained flights by the brothers entitle them to credit as inventors of the airplane, regardless of those techniques. The U.S. states of Ohio and North Carolina both take credit for the Wright brothers and their world-changing inventions — Ohio because the brothers developed and built their design in Dayton, and North Carolina because Kitty Hawk was the site of the first flight. With a spirit of friendly rivalry, Ohio adopted the slogan "Birthplace of Aviation" (later "Birthplace of Aviation Pioneers", recognizing not only the Wrights, but also John Glenn and Neil Armstrong, both Ohio natives). The slogan appears on Ohio license plates. North Carolina uses the slogan "First In Flight" on its license plates. The site of the first flights in North Carolina is preserved as Wright Brothers National Memorial, while their Ohio facilities are part of Dayton Aviation Heritage National Historical Park. As the positions of both states can be factually defended, and each played a significant role in the history of flight, neither state truly has an exclusive claim to the Wrights' accomplishment. While speaking at a presentation at the National Museum of the United States Air Force in Dayton, Neil Armstrong joked that there is enough credit for both states: North Carolina provided the right winds and soft landing material and Dayton provided the know-how, resources and engineering.