What wing-flapping aircraft did Leonardo da Vinci design for human flight?

Leonardo da Vinci designed an ornithopter for human flight by imitating the flapping wings of birds.

The word ornithopter comes from Greek roots meaning “bird” and “wing.” Leonardo's surviving notes and sketches show several attempts to understand how a person might power wings with the legs, arms, or both. His studies included bird anatomy, wing movement, balance, and the action of air.

Leonardo did not build a successfully flying human-powered ornithopter. Human muscles cannot provide the same power-to-weight ratio as the muscles of flying birds, and the proposed mechanisms would have been too heavy and inefficient. Some of his designs also resemble bat wings rather than bird wings, but ornithopter is the standard name for a machine that flies by flapping wings.

The idea later influenced experimental aviation. Modern ornithopters have flown, especially small radio-controlled models, but Leonardo's designs remained conceptual inventions from the Renaissance rather than working aircraft.