IMHO it is necessary to have Player party vs Dragon combat, in a place where logically the dragon cannot or does not intend to fly (e.g. First Garden).
As for turn-based dragon flight - it would be possible to do this if:
1) You could at most execute one dragon breath attack per turn,
2) you had to move the full number of spaces per turn while flying
3) If you wanted to attack melee, you'd have to land, and still move the full number of spaces to end your turn
4) while attacking melee, you'd be penalised in movement (wings, yo!)
5) to take off, you'd have to use up all your points, while moving in a single direction
6) cannot fly in any in-doors environment
