Leonardo da Vinci designed an ornithopter with flapping wings inspired by birds.
An ornithopter is an aircraft intended to fly by moving wings up and down, rather than by using fixed wings or propellers. Leonardo studied birds, bats, and the mechanics of wing movement while developing several flying-machine concepts during the late fifteenth and early sixteenth centuries.
His sketches explored frames, wing joints, pedals, and levers that could transfer a pilot’s muscle power into wing motion. The designs were inventive, but a human pilot could not supply enough sustained power to lift the heavy machine. Leonardo therefore did not produce a successful man-powered aircraft.
The word “ornithopter” applies to a whole class of aircraft, not just one Leonardo design. This is a common source of confusion: Leonardo’s machines were proposed ornithopters, while later experimental aircraft also used the same principle. Modern ornithopters have flown, usually with lightweight structures or powered mechanisms, but they do not validate every detail of Leonardo’s original designs.