I played 2 NFP scenarios so far and they are from fall of France both. If I gave 2 air combat cards to allied player he became to dangerous. I read some history books about the Invasion of France and all books said that most of the allied planes were destroyed in the early days of invasion. So I made my on rule with NFP air combat cards. My rule is this: The player with air superiority draws one more combat card and his opponent draws one less air combat card. If neither player has air superiority, Both players take just one air combat card. In my both scenarios played so far (see my latest two After Action Review topics) I gave only 1 air combat card to the allied player and it worked well. Even with this improvement allies were dangerous in the air but this adds a bit more strategy for axis player (they must eliminate the first air unit attacking because allies will not have any air combat cards next turns). If you are thinking about any more improvements feel free to comment them here.