Leonardo da Vinci sketched an ornithopter as a human-powered flying machine with flapping wings.
The word ornithopter comes from Greek roots meaning “bird” and “wing.” Leonardo studied birds, bats, and the mechanics of flight, then applied his observations to designs in the late fifteenth and early sixteenth centuries. His sketches show wings intended to imitate the motion of a bird’s wings.
Leonardo’s proposed machine was not successfully built or flown. Human muscles cannot provide enough sustained power for a practical flapping aircraft of the size he imagined. The design is therefore a significant study in aeronautical history rather than a working aircraft.
An ornithopter is often confused with Leonardo’s aerial screw, which resembles a helicopter. The distinction is simple: an ornithopter generates lift through flapping wings, while a helicopter uses rotating blades. Modern experimental ornithopters have flown, but they use improved materials and propulsion.