[StainlessSteelCynic]

Purely from the point of view of creating scenarios, having a handful of aircraft flying opens up some opportunities. I'm not thinking so much of PCs getting to use said aircraft (at least, not straight away) but more along the lines of missions in support of aircraft such as the PCs being sent out to: - collect parts/fuel/ammo, locate pilots/crew/mechanics/technicians, rescue downed aircrew, destroy threats to the operation of the aircraft (e.g. AAA, other aircraft), provide early warning of enemy aircraft and so on.

I'm also thinking of the fear factor of both allied and enemy forces who would have to keep an eye on the sky and the potential for worry while they try to identify an approaching aircraft.
Even with the prevalence of ManPADS, SAMs & AAA before the war, they will be, like everything, reduced in overall numbers or be less effective due to lack of ammo, transport or trained personnel or they might be concentrated around important locations (and perhaps the PCs are tasked with plotting the locations of enemy air defences). So rather than having umbrella type coverage, there will be AA coverage in certain areas with the potential for AA being located in areas thought safe - should make any flight into the area a long and twisting flight, probably at low level with the added fear that maybe they'll run into something!