Dorian Walker, Chairman of Friends of Jenny, works on the frame of an aircraft, May, 4, 2017 at Bowling Green, Kentucky. The Curtiss JN-4 is possibly North America's most famous World War I aircraft. It was a twin-seat, student in front of instructor, dual-control biplane. Its tractor propeller and maneuverability made it ideal for initial pilot training. It was widely used during World War I to train begining pilots, with an estimated 95% of all trainees having flown a JN-4.