Leonardo da Vinci’s flapping-wing flying machine was an ornithopter.
An ornithopter is an aircraft designed to fly by moving wings up and down, rather than by using fixed wings or a continuously rotating rotor. Leonardo studied birds and bats and made several sketches exploring how human-powered flight might work.
His designs were visionary but not practical for a person to operate. Human muscles cannot produce enough sustained power to flap wings of the required size, and the proposed structures would have been difficult to control. Leonardo’s work nevertheless showed a systematic interest in aerodynamics, anatomy, balance, and propulsion.
The word “ornithopter” comes from Greek roots meaning “bird” and “wing.” Modern experimental ornithopters use motors or other mechanical power, but Leonardo’s famous designs belong to the early history of flight rather than to successful aviation.