Leonardo da Vinci’s human-powered flying-machine concept was an ornithopter.
An ornithopter is an aircraft designed to fly by flapping wings, imitating the motion of birds or bats. Leonardo studied birds extensively and produced several sketches of winged machines during the late fifteenth and early sixteenth centuries. His designs generally placed a person inside or beneath a framework, with pedals, levers, or other mechanisms intended to move the wings.
Leonardo understood that human muscles alone would probably not provide enough power for sustained flapping flight. Even so, his studies were important because they treated flight as an engineering problem involving lift, balance, weight, and wing movement. His notebooks include observations about bird anatomy and air currents alongside machine drawings.
An ornithopter is different from Leonardo’s helical aerial screw, which is often compared with a helicopter. The ornithopter depends on flapping wings, whereas a helicopter uses rotating blades to generate lift.