What Leonardo da Vinci machine had wings that flapped like a bird’s?

Leonardo da Vinci’s bird-like flying-machine designs are known as ornithopters.

An ornithopter is an aircraft intended to fly by flapping wings, rather than by using propellers or fixed wings. Leonardo studied bird and bat flight and drew several machines with wings, frames, and mechanical linkages intended to transfer human effort into flapping motion.

His ornithopters were never successfully flown. Human muscles cannot provide enough sustained power to lift a pilot with the heavy wooden structure Leonardo imagined, and the designs did not have the efficient lightweight materials used in modern aircraft.

The word “ornithopter” comes from Greek roots meaning bird and wing. Leonardo’s work is nevertheless significant because it combined anatomical observation with mechanical experimentation and helped establish a long tradition of biomimetic flight research.