Ornithopters

An ornithopter (from Ancient Greek ὄρνις (órnis) 'bird' and πτερόν (pterón) 'wing') is an aircraft that flies by flapping its wings. Designers sought to imitate the flapping-wing flight of birds, bats, and insects. The term covers a wide range of possible designs. Ornithopters are typically built on the scale of the animals they emulate, however larger, crewed fliers have also found experimental success. Crewed ornithopters are generally powered either by engines or by the pilot.