Dragons proper are supposed to have six limbs, and are a massive deviation from real tetrapods. Draco volans is a small gliding lizard with a membrane stretched between elongated ribs.

Yes, Coeleosauravus was a glider, and wouldn't have had powered flight, which is . It was much more like Flying Lemurs (which don't really fly and aren't lemurs) and sugar gliders. Flying foxes are actually fruit bats, and really do fly.