Leonardo da Vinci’s bird-inspired flapping aircraft concept was an ornithopter.
An ornithopter is an aircraft designed to fly by flapping wings, imitating birds, bats, or insects. Leonardo studied bird anatomy and flight extensively and made several sketches of machines with wings moved by a person inside the frame.
His designs often included a prone pilot who would operate levers, pedals, or other mechanisms to move the wings. Leonardo understood that human muscles could not produce the same power-to-weight ratio as a bird’s flight muscles, but he continued investigating flapping flight as a mechanical problem.
Leonardo’s ornithopters were concepts rather than proven aircraft. They should not be confused with his glider studies, which relied on fixed wings and rising air rather than flapping motion. The word itself comes from Greek roots meaning “bird” and “wing,” and it remains the standard technical term for a flapping-wing aircraft.