Pterosaur fossils have been known since the 1700's. We have quite a few, beautifully preserved fossils, so we can tell a great deal about them. I discussed in some detail the major features of their anatomy by describing one particularly well-preserved fossil. Discussed similarities and differences between them.
Pterosaurs have the same general stratigraphic range as dinosaurs do.
Compared similarities and differences with bats and birds in terms of flight abilities, also to flying squirrels and other gliding animals.