Godzilla belongs in the sea and land, not the air. If you give him the ability to fly, it won't be long before they make a scene a lot like the original Rodan where they're having a dogfight with Godzilla.
It was weird enough in Godzilla vs. Megaguirus when he jumped in the are and did that body slam, stomach flop thing, what's even worse is that he didn't seem that lively as he done it!



