What type of flying machine did Leonardo da Vinci model on the wings of a bat?

Leonardo da Vinci studied an ornithopter, a flying machine intended to rise through flapping wings modeled on birds and bats. The word ornithopter refers to an aircraft whose wings generate lift by flapping rather than by remaining fixed.

Leonardo examined the anatomy and motion of birds, bats, and other flying animals while developing his aeronautical ideas. His sketches explored wing structures, control surfaces, and the muscular effort that would be needed to power them. Some proposed designs used a human operator, but human muscle power is not sufficient to sustain the required flapping flight.

An ornithopter is different from a glider, whose fixed wings generate lift while moving forward, and from Leonardo’s helical aerial-screw concept. Leonardo’s ornithopter studies were influential observations, but no confirmed human-powered Leonardo flying machine achieved flight.