Leonardo da Vinci designed an ornithopter, a human-powered flying machine intended to copy the flapping motion of bird wings.
Leonardo studied birds, bats, and the mechanics of flight throughout his notebooks. His ornithopter concepts used large wings connected to pedals, levers, or other mechanical parts so that a person could try to produce lift through repeated flapping.
The machines were never proven to fly. Human muscles cannot provide the power-to-weight ratio needed for a practical flapping aircraft of the proposed size, and Leonardo's designs did not include a modern engine.
An ornithopter is not the same as a helicopter or a glider. A glider depends on fixed wings and moving air, while a helicopter uses powered rotors. The term covers any aircraft that flies by flapping wings, whether the wings are moved by a person, an engine, or another mechanism.