Leonardo da Vinci sketched an ornithopter, a human-powered aircraft with wings modeled on a bird’s wings.
The word ornithopter means a machine that flies by flapping its wings. Leonardo studied birds in detail and produced several designs in which a pilot would lie or stand inside a framework and operate wing mechanisms. Some sketches used pedals, levers, or hand controls to transmit human movement to the wings.
Leonardo understood that birds generated lift and thrust through coordinated wing motion, but his machines could not realistically overcome the limited power available from human muscles. A human-powered flapping aircraft therefore remained impractical with the materials and technology of his time.
These designs are often confused with Leonardo’s gliders and aerial screw. An ornithopter flaps its wings, a glider relies on fixed wings and air currents, and the aerial screw was a separate rotary-lift concept. None of Leonardo’s aircraft designs is known to have flown successfully.