I have thought about this before actually. My mind shutters at the thought of a flying mudcrab. Just a scary thought.
Then you've never encountered a Cliffcrab. You hear the epic music while high upon a cliff close to the edge, instantly looking up to the sky for fear of dragon's ninja plucking you out of nowhere and throwing you into the wind...only to have your ankles nipped at by a small crab. Many a warrior had needed to change their loincloth after such an encounter.
But I do hope there are more flying enemies besides dragons.