Leonardo da Vinci studied ornithopters, aircraft intended to fly by flapping wings like birds.
The word ornithopter comes from Greek roots meaning “bird” and “wing.” Leonardo filled notebooks with observations of birds, bats, and the mechanics of flight. He examined wing shape, joints, feathers, balance, and the relationship between a bird’s body weight and its wing area.
His proposed machines generally used human-powered mechanisms to move large wings. Some designs placed the pilot inside a framework and used pedals, levers, or other movements to drive the wings. Leonardo eventually recognized that human muscles could not provide enough power for a full-sized flapping aircraft, but his studies still contributed to the history of aeronautical thought.
An ornithopter is not the same as a glider or helicopter. A glider depends on fixed wings and air currents, while an ornithopter generates lift through repeated wing motion. Leonardo’s ornithopters remained designs rather than successful flying machines.