A simple solution is on the right click where you can select the mission.
A = auto
I = intercept 50% (readiness)
O = optimal intercept 75% (readiness)
G = ground support
so on and so on.
This type of SOP would bring a level of realism to air support, make surprise beach landings much more difficult, and generally get tac air to do what it was best at: interdiction. So, if a unit uses, say, more than 1/4 of it's "movement points" (I don't recall the correct name), then an air unit within range, tasked with interdiction, could respond.
Fighters would be able to intercept air unit in mid-flight, instead of having to do it at the target area (which could be out of range).
So overall, greater realism and still quite playable.