It should be possible to add air support by tweaking the ranges of Axis airbases. If you set the range to 20,000 km (or another very high value) and adjust the chances of a response to between 60 and 70% it should mean every Axis air base will respond to your contact reports.
There will need to be a load of testing for this as you don't want to swamp the target with aircraft (adjusting the % chance of a response is the best way of seeing to this) and you'll need to be disciplined enough to just send one contact report - if you send too many contact reports then you'll end up with 50 or 60 Axis aircraft responding to your call every time (fun, but unlikely!). It will be a pretty crude way of solving the problem and you'll end up with all types of aircraft but it should work.
Let me think about this one
