Leonardo da Vinci designed an ornithopter as a human-powered flying machine modeled on the flapping wings of birds and bats.
Leonardo studied bird flight closely and filled notebooks with sketches of wings, joints, feathers, and airflow. His proposed ornithopter used a human operator’s leg and arm movements to drive large wings. The design reflects Renaissance attempts to imitate nature mechanically, rather than using an engine or propeller.
Leonardo’s machine was never built as a practical aircraft, because a person could not generate enough sustained power to lift the structure. That limitation distinguishes it from later successful airplanes, which relied on engines and fixed wings. The word “ornithopter” describes the mechanism, not a particular Leonardo model: it means an aircraft that flies by flapping wings.
Leonardo also drew gliders and studied parachute-like devices, but those are different concepts. An ornithopter’s defining feature is active wing flapping.