Leonardo da Vinci’s human-powered, birdlike flying-machine concept is commonly called an ornithopter.
An ornithopter is an aircraft intended to fly by flapping wings, rather than by using fixed wings or a rotating rotor. The word comes from Greek roots meaning “bird” and “wing.” Leonardo filled notebooks with studies of birds, bats, wing movement, air resistance, and the mechanics needed to imitate natural flight.
His drawings show several proposed arrangements, including machines in which a pilot would move wing mechanisms with the hands and feet. Leonardo understood that human muscles alone would probably not provide enough power for a large flapping aircraft. Some designs therefore explored mechanical assistance, while others were mainly investigations of the principles of flight.
No evidence shows that Leonardo successfully flew an ornithopter. His work nevertheless helped connect artistic observation with mechanical and aerodynamic analysis. Modern ornithopters do exist, including small radio-controlled aircraft, but they do not establish that Leonardo’s full-scale human-powered concepts were workable. The designs are best described as visionary studies of biological flight rather than completed aircraft.