The Wright Flyer (often retrospectively referred to as Flyer I or 1903 Flyer) was the first successful powered aircraft, designed and built by the Wright brothers. They flew it four times on December 17, 1903 near the Kill Devil Hills, about four miles south of Kitty Hawk, North Carolina, U.S.

The U.S. Smithsonian Institution describes the aircraft as "...the first powered, heavier-than-air machine to achieve controlled, sustained flight with a pilot aboard." The Fédération Aéronautique Internationale described the 1903 flight during the 100th anniversary in 2003 as "the first sustained and controlled heavier-than-air powered flight."

The Flyer was based on the Wrights' experience testing gliders at Kitty Hawk between 1900 and 1902. Their last glider, the 1902 Glider, led directly to the design of the Flyer.

The Wrights built the aircraft in 1903 using 'giant spruce' wood as their construction material. The wings were designed with a 1-in-20 camber. Since they could not find a suitable automobile engine for the task, they commissioned their employee Charlie Taylor to build a new design from scratch. A sprocket chain drive, borrowing from bicycle technology, powered the twin propellers, which were also made by hand.

The Wright brothers, Orville (August 19, 1871 – January 30, 1948) and Wilbur (April 16, 1867 – May 30, 1912), were two Americans 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 developing a reliable method of pilot control as the key to solving "the flying problem". This approach differed significantly from other experimenters of the time who put more emphasis on developing powerful engines. Using a small homebuilt wind tunnel, the Wrights also collected more accurate data than any before, enabling them to design and build wings and propellers that were more efficient than any before. Their first U.S. patent, 821,393, did not claim invention of a flying machine, but rather, the invention of a system of aerodynamic control that manipulated a flying machine's surfaces.