Leonardo da Vinci’s human-powered birdlike flying machine was an ornithopter. The word ornithopter comes from Greek roots meaning “bird” and “wing,” and describes an aircraft that flies by flapping its wings rather than using propellers or fixed wings.
Leonardo filled notebooks with studies of birds, bats, wing structure, and air resistance. His designs generally placed a person inside a frame who would operate wing mechanisms with the arms and legs. The drawings reveal close observation of anatomy, but the proposed human power was not enough to lift the machine.
Leonardo’s ornithopter was never built and successfully flown. Modern ornithopters use engines or motors, while experimental human-powered aircraft normally use large, lightweight fixed wings. The design is therefore best understood as an important Renaissance investigation of flight, not as a working aircraft.
The ornithopter is often confused with Leonardo’s aerial screw, which used a helical surface and is sometimes described as an early helicopter concept. The two ideas represented different approaches to leaving the ground.