Leonardo da Vinci designed an ornithopter, a flying machine intended to fly by flapping birdlike wings.
The word ornithopter comes from Greek roots meaning “bird” and “wing.” Leonardo studied birds, bats, and the mechanics of flight, then produced several designs in his notebooks. In these concepts, a human pilot would lie or stand inside a frame and operate wing mechanisms using arms, legs, or both.
Leonardo correctly recognized that flight depended on lift and carefully observed how birds changed the shape and angle of their wings. However, a human body could not provide enough power to flap wings large enough to carry a pilot. The designs therefore remained unbuilt experiments on paper rather than successful aircraft.
An ornithopter is not the same as Leonardo’s air screw. The air screw uses a helical surface to seek vertical lift, while an ornithopter imitates the flapping motion of birds or insects. Modern unmanned ornithopters have flown, but they use lightweight materials and powered mechanisms unavailable to Leonardo.