Pterosaurs, flying reptiles that lived at the time of the dinosaurs, flew like paper planes by gliding slowly on tropical breezes, researchers say.
Scientists used fossils to help build models of pterosaur wing sections and tested them in a wind tunnel.
They found that pterosaurs would have been too slow and flexible to brave strong and stormy winds.
So it's thought the creatures flew slowly and landed gently to protect their paper-thin bones.
They think this might explain how some of the creatures were able to grow to be the size of a small plane!