The ability to bank is essential to controlled flight. Otto Lilienthal did it by shifting his weight, but for the much larger Wright Flyer the solution was to make one wing produce more lift than the other by twisting them in opposite directions.
“Wing warping,” as this approach was called, was satisfactory for very slow airplanes, but faster ones required more rigidity, and by around 1908 or 1909 the idea had arisen of replacing part of the trailing edge of a wing with a hinged, controllable flap. Actually, a prescient Englishman, Matthew Boulton, had patented the idea in 1868, when airplanes were still a thought experiment. His invention had been forgotten, however, by the time real airplanes came into being. Despite the early invention of the aileron, wing warping continued to be used, even on some fighters, as late as 1916.
