They both seem exactly alike to me...
Most Helpful Guy
There is no evidence dragons actually existed but in my opinion that doesn't mean some sort of flying lizard/dinosaur couldn't have been what people thought was a dragon back then.
You have to wonder though even the greatest lies and myths have a kernel of truth in them, you have the wonder were the legends came from especially with there being so many all over the world and with them being very similar.
Anyway the difference between dinosaurs and dragons at least the ones in myth is that dinosaurs there is great variety in terms of species, dragons are pretty consistent, mythological dragons breath fire, dinosaurs do not and so on and so on.1