Anti Aircraft in General & MGs on airfields specifically?

[Blitzen]

In advaned settings I've been trying to dial in a more vigorous anti aircraft defence on both sides without success.I have yet to see any flak. Also I have been chased back to myhome airfield by flocks of Yaks & Migs .....arriving there I had hopes that my own airfield personel would be awake to the new Russian threat & take a few potshots at my pursuers-no such luck. I have not pressed the right set up buttons .Can someone help?