Leonardo da Vinci studied an ornithopter, a flying machine intended to imitate the wingbeats of birds.
The word ornithopter comes from Greek roots meaning “bird” and “wing.” Leonardo filled notebooks with observations of birds, bats, and the mechanics of wings. His proposed machines generally used a human operator to move large wings through pedals, levers, or other mechanical linkages.
The designs reveal Leonardo’s belief that careful study of natural flight could guide engineering. However, a person cannot supply enough power through human muscles to flap wings large enough for sustained powered flight. Leonardo’s ornithopters therefore remained studies and sketches rather than working aircraft.
An ornithopter differs from a glider, which gains lift from forward motion without flapping, and from a helicopter, which uses rotating blades. Modern experimental ornithopters do exist, but they are not evidence that Leonardo’s machines flew.