I'm new to this game and never played anything from GG before.
Anyway, such an air system was a huge disapointment for me and barely made me quit playing because I could not figure out how to use it efficiently. Moreover, it's also the very the first step of each turn, and one must spend quite a lot of time right at the begining to sort out how it is working (or let everything to auto). I might have restarted several dozens of campaign games after playing a few German turns in order to try those different AD settings.
So, I also couldn't make my AS working against enemy airlifted supplies, or anything else that could be worth such an insane level of operational losses inflicted to my fighter force during AS missions. Auto interception (Fighter groups based in range while not being assigned to any AD) are inflicting very slight damage to enemy transport missions while their attrition rate is also quite low.
Comparatively, it seems ridiculous to me that a huge formation of unescorted (but fast) Ju-88 during a bombing raid might suffer up to 100% casualities if intercepted by a bunch of I-153s (a slower biplane) while any transport mission, even without protection, will deliver hundreds of tons of supplies close to the hex where a full Geschwader of enemy fighters were actually based.
Whatever the fighter setup, airlifted supplies seems to be able to get thru (for both side).
Finally, so many things are looking so weird in the Russian sky that I gave up trying and dumped all my airforce before even restarting the first campaign turn (excepted the german fighters and transport). Then, my über pilots are killing scores of enemy, like 30+ to 1, and the only thing I have to do is to rebase them as close to the front as possible during the movement phase.
Now, even that bit is painfull to do with an interface probably designed around 1991. (well, GG should have a look at the ergonomics of 2021 software too !).