What flying-machine type did Leonardo da Vinci study using flapping wings?

Leonardo da Vinci studied an ornithopter, a flying machine intended to fly with flapping wings.

The word ornithopter combines Greek terms meaning bird and wing. Leonardo’s studies of these machines were inspired by the anatomy and flight of birds and bats. His notebooks contain many sketches of wings, frames, joints, and mechanisms intended to transfer human motion to wings.

Leonardo understood that birds generate lift and thrust through coordinated wing movements, but his human-powered designs could not provide enough power for sustained flight. A person’s muscles are much weaker relative to body mass than the flight muscles of a bird, making a large flapping machine impractical without another power source.

An ornithopter is not the same as a glider, which relies on forward motion and fixed lifting surfaces, or a helicopter, which uses rotating blades. Modern experimental ornithopters have flown, often with lightweight mechanical or motorized systems, but Leonardo’s versions remained designs and studies rather than successful aircraft.