Leonardo da Vinci designed an ornithopter, a flying machine intended to imitate the flapping wings of birds.
The word ornithopter comes from Greek roots meaning “bird” and “wing.” Leonardo studied birds extensively and filled notebooks with observations about their wings, balance, muscles, and movement. He hoped that a machine using similar principles might carry a person through the air.
His ornithopter concepts generally used large wings operated by human power through pedals, levers, or other mechanical linkages. The designs show careful attention to anatomy and mechanical motion, but human muscles cannot produce enough sustained power to flap wings large enough to lift a person.
Leonardo also explored gliding and rotary flight, so not every flying-machine drawing belongs to the ornithopter category. The term specifically refers to aircraft that generate lift by flapping wings, whether powered by people, engines, or other mechanisms.