Leonardo da Vinci designed ornithopters, winged aircraft intended to fly by flapping like birds or bats.
His notebooks contain studies of bird anatomy, wing movement, balance, and air currents. Several machine concepts use large wings connected to mechanisms that a pilot would operate. Leonardo understood that flight required more than simply copying a bird’s shape: the machine also needed lift, propulsion, and control.
An ornithopter is defined by flapping wings, whether it is powered by a person, an engine, or another mechanism. Leonardo’s designs were generally human-powered and lacked a practical power source strong enough to make sustained flight possible. They were therefore inventive studies rather than successful aircraft.
The term comes from Greek words meaning “bird” and “wing.” Modern experimental ornithopters have flown with engines or remote control, but they remain distinct from fixed-wing airplanes and rotary-wing helicopters.