What Leonardo da Vinci machine was designed to flap wings like a bird?

Leonardo da Vinci designed ornithopters, machines intended to fly by flapping wings like birds.

The word ornithopter comes from Greek roots meaning “bird” and “wing.” Leonardo studied birds, bats, and human anatomy while developing several flying-machine concepts. His designs commonly placed a pilot inside a frame who would operate wings through pedals, levers, or other mechanical controls.

These machines were based on the idea that imitation of bird flight could produce human flight. In practice, a human pilot could not generate enough power to flap wings of the required size, and the proposed structures were too heavy for successful takeoff. Leonardo therefore produced plans and observations rather than a functioning ornithopter.

An ornithopter is not the same as a glider or helicopter. A glider depends on fixed wings and moving air, while a helicopter uses powered rotary blades. Leonardo’s ornithopter studies nevertheless contributed to the long history of attempts to understand and reproduce animal flight.