You say that the player will know what planes are available to both sides.When setting CAP, the player does not know what air missions the phasing player is going to fly. However, he does know what planes are available for both sides. Therefore, the player can make CAP assignments conditional upon the number, quality, and location of enemy air units. Also included in the conditionals can be references to what is in the target hexes, weather, and the status of other units. For example, the CAP missions against Port Attacks might only be flown if a ‘sufficient’ number of naval units are in the port. The player might also want to base the go/no go decision on whether there are other “good things” for the fighter to do (e.g., don’t fly the CAP mission but keep the fighter available for use later in the impulse/turn).
About the enemy available planes more specifically, it would be good if the player knew the available enemy planes considering the specific hex he chose.
For instance if I choose the Ploesti Oil wells, I'd be happy to have the information about enemy planes that can go to Ploesti, with their cumulative air to air strengh (as if they were aligned to fight) and their total strat / tactical / naval air strengh.

