Leonardo da Vinci studied an ornithopter, an aircraft intended to fly by flapping wings.
The word ornithopter comes from Greek roots meaning “bird wing.” Leonardo’s late-fifteenth- and early-sixteenth-century sketches explored human-powered flying machines with wings that moved through the air. Some designs drew on bird anatomy, while others resembled the membrane wings of bats.
Leonardo carefully observed birds and wrote about lift, balance, wind, and wing movement. However, a human pilot could not generate enough power with Renaissance mechanisms to flap wings on the scale required for sustained flight. His studies therefore remained experimental designs rather than successful aircraft.
An ornithopter differs from a glider, which flies with fixed wings, and from a helicopter, which uses rotating blades. Modern ornithopters have been built as small mechanical or radio-controlled models.