Leonardo da Vinci designed ornithopters to imitate the flapping flight of birds.
An ornithopter is an aircraft intended to fly by moving wings up and down. Leonardo studied bird anatomy, wing structures, and the mechanics of flight extensively. His drawings show human-powered designs in which a pilot might operate wings through pedals, levers, or other linkages.
Leonardo correctly recognized that birds use more than simple upward and downward motion: wing shape, air resistance, balance, and body weight all matter. However, a human-powered machine with birdlike flapping wings could not provide enough power for practical sustained flight with Renaissance materials and muscles.
The ornithopter differs from the aerial screw, which uses a rotating helical surface, and from the parachute, which descends rather than generates powered flight. Leonardo’s work on these machines helped establish a systematic approach to studying flight, even though none became an operational aircraft in his lifetime.