Leonardo da Vinci studied an ornithopter, a human-powered aircraft designed to fly by flapping wings.
The word ornithopter means a flying machine whose wings produce lift through a birdlike flapping motion. Leonardo examined bird and bat flight and produced sketches of wing structures, frames, and mechanical systems intended to transfer human effort into wing movement.
His studies were part of a broader investigation of flight that also included gliding and parachute concepts. The flapping-wing designs were not powered by an engine, because engines capable of providing useful aviation power did not exist in Leonardo’s time.
Leonardo’s ornithopter studies did not result in a proven flying aircraft. Modern aircraft generally use fixed wings or powered rotors instead. The historical importance of the sketches lies in their close observation of anatomy, air resistance, and mechanical motion.