There's already some of them present E.G. in Odessa and Rakowice IIRC. Maybe some other maps aswell.
Unless you intent to turn every map into aircraft graveyard...
We dont really need plane graveyards, well.. maybe one could be cool, but it would be nice to see some Russian planes, all we have now is the JU-52, BF-109 and JU-87, why not spice it up a bit and add a MIG-3, YAK-9, IL-2, or PE-2?
The problem with making them equivilant to arty strikes is that, even though they were starting to develop close-air-support during the war, I don't believe they ever had the ability for a sergent to call in on a radio and recieve an immediate airstrike.
So replacing the arty strikes with aircraft = gamey and non-historical
But adding in flights of airstrikes and simulated "random" arty strikes = Realistic and better
Indeed, neither the Germans nor the Russians had that kind of abillity, airstrikes could be called, but it took planning and time, it is nothing that could possibly happen within the time of a round of RO.
Even "random airstrikes" are probably a bad idea.. aircraft did not drop small neat packages like arty shells, usually on the Eastern front, we are talking a minimum of 2x 50kg bombs, but 2x 100kg, 1 or 2x 250kg and 1x 500kg would be the norm (and thats per aircraft, and only Jabo's and air-to ground planes, bombers carry much more), thouse are very big booms within the size of a RO map, even the largest of them, so done realistically, they would be extremely annoying!
Stukas had sirens only in 1940 France campaing.
Removed later on as enemy got it's act together and actually formed some AA, why alert enemy of yuor presence before killing him.
That's news to me, got a source?
I don't mean to nitpick but I believe the western allies where able to call in air strikes later in the war through radio as well as aircraft being on standing patrols called "the cab rank". Also during the early blitzkrieg successes in Europe, the German army often had a Luftwaffe intermediary that could forward targets to his command.
The More You Know...
It is definately true that the Yanks had the best abillities, but still, this is nothing that would take place within the timescale of an arty strike (and thats what it'd have to be if it was to be usefull in RO), it took time, a round of RO will probably have started and ended before the planes could recive the order and start heading twords the location.. even today an insta airstrike (as in, within minutes) is practically impossible unless you have planes circling the area allready.