Leonardo da Vinci sketched an ornithopter with two large wings modeled partly on bats.
An ornithopter is an aircraft intended to fly by flapping wings, imitating birds, bats, or insects. Leonardo filled notebooks with observations of bird flight and explored machines in which a human pilot would power the wings through pedals, levers, and other mechanical linkages. His designs were among the best-known early attempts to apply engineering analysis to biological flight.
Leonardo’s ornithopter was never built as a practical flying aircraft, and a human pilot would not have had enough muscle power to operate such large wings. The term does not mean any aircraft with wings; it specifically refers to flapping-wing flight. Leonardo also studied gliding and proposed other aerial mechanisms, so his notebooks contain several different flight concepts rather than one finished aircraft.