[PatG]

Sorry but I can't see your average battalion commander ringing up the local airbase and saying "Give me 3 flights of fighter bombers and cover them with two flights of fighters".

More like the Battalion CO says to his air force liaison - "We need air support and it has to come through!!!" The liaison talks to his boss who then looks at his list of available AC and orders up two flights of FB and seeing that the ground pounders are desperate, reluctantly pulls a couple of fighters off CAP leaving a hole elsewhere and adds them to the strike force. The grunts never see the fighters, just the FBs rolling in.

If you want a realistic change to air support:

Outside of designed scenarios, the player should only be able to pay for unspecified "air support" with the exact composition left to the AI. Whatever comes through is assumed to have had enough fighter cover to make it to the battle area unmolested - just as it works now.