Pterosaurs were entirely distinct and evolved flight independently from the Aves lineage, indeed they weren’t even dinosaurs (they were related to dinosaurs via

Pterosaurs were entirely distinct and evolved flight independently from the Aves lineage, indeed they weren’t even dinosaurs (they were related to dinosaurs via common superclade Archosauria, like modern reptiles and crocodilians). They generated lift with flaps of skin much more similar to bat wings than bird wings. Had they survived the K/Pg extinction, we might indeed have flying reptiles that don’t look much like wings.