Leonardo da Vinci sketched an ornithopter, a machine intended to fly by flapping bird-like wings.
The word ornithopter combines Greek roots meaning “bird” and “wing.” Leonardo studied birds extensively and filled notebooks with observations about wing movement, balance, air currents, and the mechanics of flight. His proposed machines included frameworks with wings operated by a human pilot’s arms or legs.
Leonardo understood that birds generate lift and propulsion through coordinated wing movements, but human muscles alone cannot power a sufficiently large aircraft. His ornithopter designs therefore remained experimental drawings rather than successful aircraft.
Some Leonardo sketches show a pilot lying or standing within a wooden framework. They are often confused with his glider concepts, which use fixed wings. An ornithopter is specifically defined by flapping wings, whether powered by a person, an engine, or another mechanism.