Well obviously the whole ground vehicle concept is for the Eastern front. The Luftwaffe and the VVS were tactical airforces and their original purpose was to support ground units.
If you want to simulate the Eastern front properlu you have to have the ground vehilces in the mix.
I'm guessing it will be as mentioned that you will have AI tanks with you and you give them instructions just like we are 'supposed' to have with radio commands for our AI wings.
I'm also guessing that mission builders can build AI tank battles and if you want you can jump into a tank just like we can do with aircraft, or you can just let the AI battle it out.
This could be interesting as it's going to encourage more divesity in the air as we'll have more people willing to get into ground pounding, and they'll need escort cover. So rather than dogfighting for the hell of it, air superiority will actually be the aim of the fighters so that the bombers and fighter bombers can get through and anhilate the objective.
You can say that we have this already but I reckon it's more enticing to players when they know that a vehicle may be manned by a human rather than AI. So you are more tempted to get into your Ju 87 or IL2 and go drop a few bombs on the guy!