The Wright brothers were not the first people ever to fly, because people had flown in balloons and attempted gliders long before them, but what was new was a powered airplane that could be controlled. The Wrights pioneered basic tenets of modern aeronautical engineering, such as using a wind tunnel and flight testing as design tools, and the Smithsonian says their basic design elements and approach to aeronautical engineering have been used in all successful airplanes ever since. In May 1899 Wilbur wrote to the Smithsonian Institution and requested its publications about flight. The Smithsonian recommended Progress in Flying Machines, a history of aviation that Octave Chanute published in 1894. Based on their reading, the Wrights believed that Otto Lilienthal of Germany had been the most successful researcher before them and had collected the most reliable data, particularly his calculations on air pressure. Lilienthal made nearly 2,000 manned glider flights, and his wings had a gentle curve for lift, but his only means of controlling the gliders was shifting his weight. Samuel Langley, secretary of the Smithsonian Institution, flew a steam-powered model called an aerodrome in 1896, the first large-scale heavier-than-air machine to fly, though it had no steering capability.

A wing makes lift when air meets it, so making different amounts of lift on each end of a wing would make one side rise more than the other and bank the whole aircraft. Because wing warping was based on the air and not on body weight, it did not limit the size of the aircraft, as shifting body weight did. Then their 1901 glider developed only one-third of the lift that Lilienthal's data predicted. They also met adverse yaw: when the wings were warped to roll the aircraft, drag increased on the upper wing, and the aircraft twisted the opposite way. Roll tilts the wings from side to side, pitch moves the nose up and down, and yaw steers left or right; an airplane has to be controlled in all three ways. Wing warping meant twisting the tips of the wings in opposite directions with lines the pilot pulled. Their mother, Susan, had taught the brothers how to use tools, and the boys had asked her for mechanical help.

So they tested the data, and to make wind for a test of Lilienthal's numbers, they rode a bicycle up and down the streets of Dayton as fast as possible. Then they constructed a wind tunnel, a square tube for aiming the air, a fan that drove the air, and a balance mounted in the airstream. Each wing shape had to be tested at 45 different angles, and they recorded the experimental results on scraps of wallpaper. By mid-December 1901 they discovered, to their surprise, that Lilienthal's tables were largely correct and that the multiplier of 0.005 for air pressure, developed by John Smeaton in the 1700s and accepted as true for almost 150 years, was what was wrong. In 1901 they made approximately 100 glides between July 27 and August 17, yet the wings still did not produce enough lift and the elevator was not always reliable, and Wilbur wrote that, considering the time and money spent, they considered their experiments a failure.

Orville described the propeller problem this way: with the machine moving forward, the air flying backward, the propeller turning sideways and nothing standing still, it seemed impossible to find a starting point. The Wrights realized that a propeller is a wing that turns on a spiral course. Their propellers had an efficiency of 66 percent, compared with 40 to 50 percent for propellers designed in nineteenth-century Europe, and the two together gave a thrust of 90 pounds, just enough to rise, fly and land. Their mechanic, Charlie Taylor, made the engine's crankshaft, valves, intakes and connecting rods with shop tools primarily used for repairing bicycles. He recalled that the group made no engine drawings: one of them sketched a part on scratch paper and he fastened the sketch over his bench.

The engine's first test, on February 12, 1903, ended with a seized engine and a shattered crankcase; the Wrights reconstructed it completely and it was running smoothly by May. Their first attempt at powered flight, on December 14, 1903, failed when Wilbur lifted the airplane at too sharp an angle, which caused a stall and a hard landing that damaged the elevator. Three days later, on December 17, the first flight lasted 12 seconds, the second went 175 feet in 12 seconds, the third went 200 feet in 15 seconds, and the fourth, flown by Wilbur, went 852 feet in 59 seconds, while Langley's second full-size aerodrome had failed just nine days before. The brothers telegraphed their father: "Success four flights Thursday morning all against twenty one mile wind started from level with engine power alone." The Wrights built the engine themselves because they could not purchase one light enough for their airplane.

While negotiating the sale of their aircraft the Wrights let no one see a flight until they had a signed contract, and aeronautical activity picked up significantly during their 1906-1907 flying hiatus. By the end of May 1908 the brothers were confident they could meet the required demonstrations, and Wilbur left the Outer Banks on May 17 for Europe, where he began assembling the aircraft for the demonstration in LeMans, France. The Army wanted an airplane that could carry two people and reach at least 40 miles per hour in still air. In 1909 the airplane averaged 42.5 mph on a 10-mile test, and the extra $5,000 for the 2 mph over the requirement made the final price $30,000. They also formed the Wright Company to build and sell airplanes and train pilots, and for more than two years after 1905 they did not fly in public, to protect their invention before it was patented or sold.

On September 17, 1908, Orville took off at Fort Myer, Virginia, with Lt. Thomas Selfridge, the Army's observer, as passenger. A propeller blade fractured, and Selfridge was fatally injured, the first person to die in a powered airplane accident. Orville was severely injured, and in later years the vibration of flight irritated his sciatic nerve, a lingering condition from that crash. On July 27, 1909, Orville made a record flight of 1 hour, 12 minutes and 40 seconds with a passenger. Glenn Curtiss, a rival American aviator, developed ailerons on his own, and they eventually replaced the Wrights' wing-warping mechanism. Wilbur became preoccupied with the many patent infringement lawsuits the Wrights had filed; it was as much a matter of principle as money. Wilbur died of typhoid fever on May 30, 1912, at age 45, and his father wrote 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 steadily, he lived and died."

Orville sold his interest in the Wright Company in 1915 and became an aviation elder statesman and national folk hero. He spent the last three decades of his life serving on boards and committees related to aeronautics, including the National Advisory Committee for Aeronautics, which the U.S. government had formed within a dozen years after the first powered flight. To the Wrights, the 1903 Flyer was not a national treasure but a research tool on the path to a practical airplane. It sat in a shed behind their bicycle shop for more than a decade, and the March 1913 Dayton flood put its crates under water and mud for eleven days. As of November 2026, it is exhibited in the National Air and Space Museum in Washington, D.C. The National Park Service says that without the brothers' success at Kitty Hawk and its later commemoration, the Outer Banks might not have its modern roads, bridges and development.

Words to know

• tenets: core principles
• hiatus: pause
• efficiency: work done well
• commemoration: honoring ceremony