Orville & Wilbur Wright
1867-1948 / 1871-1912
Who
Bicycle mechanics from Dayton, Ohio, who achieved the first controlled, sustained flight of a powered, heavier-than-air aircraft - 17 December 1903, four flights, the best lasting 59 seconds.
Why it matters
They solved the problem Lilienthal's death had named: control. While funded competitors bolted engines to wings, the brothers built a wind tunnel, flew a kite, and concluded that a flying machine must be balanced like a bicycle, not steered like a boat - they invented roll control (wing-warping) as the missing third axis, and their whole aircraft was designed around the pilot's authority to unbalance it. The first flight at Kitty Hawk lasted 12 seconds and covered 37 m; by 1905 the Flyer III was circling for half an hour, and by 1908 they were selling the world its first practical airplane. They credited - and corrected - Lilienthal's lift tables in the same breath; science by bicycle light.
Lineage
Cayley defined the machine, Lilienthal proved the sky, the Wrights closed the loop with control - the last missing piece before anything could fly itself. From their wing-warping to every aileron, and from their shop-built wind tunnel to NASA's: the method is the legacy.