What might be useful is little graphical representations of combat actions - along the front line (to signify intensity and directions of attack) and along the supply lines, where you'd see where your supply lines were being attacked (assuming that enemy partisans/air raids were hidden by fog of war). Could be something as simple as a little explosion to show that ground combat was occurring, a periscope to show where a suspected enemy sub was torpedoing your supply lines, or a dive bomber to show where enemy air strikes were affecting you.
Kind of similar to your idea, I always thought it would be better from a wargamer's perspective anyway, to remove air units entirely. At least as they exist now.
In a provinceless combat system, you'd theoretically be able to build airbases wherever you want to. Paris, instead of having a province air value of, say, 6, could instead have five airbases of varying size - size 1 being the equivalent of a dirt strip with basic services to a size 10, a large multi-runway, extended runway length airbase with extensive maintenance and service capabilities.
You can base air units at these air bases. Instead of working like they do now, a whole unit representing at least 100 aircraft taking off and attacking very randomly and very unrealistically, you'd instead have a combat radius attached to the airbase. An airbase with a unit equipped with long range P-51s would have a larger combat radius than an airbase that had P-36 interceptors based at it.
OK... let me explain this fully a little more clearly.
1. You have a provinceless combat system. Because of this, you can build airbases anywhere you want on the map.
2. You can build your own air units (see my sig for further info on that)
3. The air units you build are deployed to airbases (and can be redeployed to other air bases).
4. Once deployed, the air units begin performing air operations. Of course, this is dependent on org/morale/supply levels like now.
5. Air units are given a combat radius. This combat radius is proportional - if your air unit has one fighter squadron with a 500km combat radius and 10 interceptor squadrons with 200km radii, the air unit's total combat radius will be 500km, but the strength/effects of that combat radius will be much higher at 200km than it would at 500km.
6. Air units can attack every enemy unit within it's combat radius. That doesn't mean that they will, per se, but they'll have a %chance to. When an enemy division enters a combat radius, the proportional strength of the air unit at the relevant distance from the air base will determine if the enemy unit is detected by the friendly air unit, how effective any strikes are on that enemy unit, etc.
7. Air-to-air combat occurs when combat radii of enemy forces overlap.
8. You can order air units to attack specific enemy targets (other airbases, which would possibly damage any enemy air unit based there, or bridges, cities, factories, divisions, etc). Combat will continue until the air unit is depleted (org, morale, supply or strength) or until their mission is complete (bridge destroyed, enemy division moved out of combat radius, etc). Once the combat is over, the unit will become idle (if org, morale, strength or supply is depleted) or return to their default mission (interceptors will intercept, multirole fighters will conduct air and ground attacks, tactical bombers will go after enemy units/supply lines, strategic bombers will bomb enemy installations within their respective combat radii).
Does it make sense? It's late at night here and I've been up for 18 hours.
This is an old picture I made, but it kind of helps to illustrate the point. At some time when I'm more conscious, I'll fire up MS paint and represent this better visually.
