Leonardo da Vinci designed an ornithopter as a bird-inspired, wing-flapping aircraft.
His notebooks contain studies of bird anatomy, wing movement, and air resistance. Those observations led him to imagine a machine whose wings would be powered by a human pilot or a mechanical system rather than by an engine.
Leonardo did not build a successful full-scale ornithopter, and no Renaissance technology could provide enough power for sustained human flight. The design is therefore an important aviation concept, not a working airplane. An ornithopter differs from a glider, which depends on fixed wings, and from a helicopter, which uses rotating blades.
The word ornithopter comes from Greek roots meaning “bird” and “wing.” Modern experimental ornithopters have flown, but Leonardo’s design remains famous for applying systematic observation of birds to an engineering problem.