We don’t know how pterosaurs evolved powered flight. The most primitive, probable, ancestor of pterosaurs had a bodyplan closer to that of a kangaroo. And the earliest pterosaurs like Preondactylus or Eudimorphodon were already fully capable of flight.
Sometimes it’s easy to forget just how rare fossilization is.
It requires that the species live in a climate with pretty specific conditions, to die under a few very specific circumstances, at a particular convergence of atypical events. The dino bones we have represent a tiny little fraction of the species that lived.
Plus fossils can form, emerge, and erode away before humans even evolved, thus removing our chances of knowing about species that DID have a chance to fossilize, all because bad luck said the geology between now and then would fuck our knowledge over.
I have a couple of fossils round the house and it’s so incredible to behold a creature that lived millions of years ago.