Leonardo da Vinci’s ornithopter was a flying-machine concept with flapping wings modeled on birds and bats.
Leonardo believed that studying living flyers could reveal the principles needed for human flight. His drawings show machines in which a pilot would use mechanical systems to move large wings. Some designs were inspired by bird anatomy, while others reflected the strong, membrane-like structure of bat wings.
The concept was never demonstrated as a successful human-powered aircraft. Human muscles cannot provide enough sustained power for a machine of the required size, and Leonardo did not have a lightweight engine. Nevertheless, his notebooks contain detailed observations of wing movement, air resistance, balance, and gliding.
An ornithopter differs from Leonardo’s aerial screw, which used a rotating helical surface, and from a glider, which relies on fixed wings and rising air rather than flapping.