While you could, you don't want to combine states. The point of the state pattern is to segregate states.
You can do one of two things:
- Use a pushdown automata to stack a dash state onto the air state and pop back to air once the character finished dashing. It's a feature of your state machine that, instead of tracking a single state, uses a stack (array) of states.
- Have an AirDash state that's specific to dashing in the air.