Leonardo da Vinci sketched an ornithopter as a flying machine powered by flapping wings.
An ornithopter is an aircraft designed to fly by moving wings up and down, imitating birds, bats, or insects. Leonardo studied bird flight, wing structure, air resistance, and the movement of muscles in his notebooks. His designs used a human pilot’s legs and arms to operate large wings.
Leonardo’s machine was never successfully built or flown, because human muscle power is insufficient for a practical aircraft of that size. The design is therefore an important example of Renaissance engineering rather than a working airplane.
Modern ornithopters use motors or other power sources, but they remain distinct from fixed-wing airplanes and helicopters. A common mix-up is calling every early flying-machine sketch a helicopter; Leonardo’s flapping-wing concept belongs specifically to ornithopter design.