Bats: Bats are the only mammals that are capable of true flight. They have forelimbs modified into wings and a unique skeletal structure that allows for flight.
Pterosaurs: Pterosaurs were a group of flying reptiles that existed from the Late Triassic to the end of the Cretaceous period. They were the largest flying animals of all time, with some species having wingspans of over 30 feet.