Base ack is normally no problem, now everyone and his donkey mass-spawn wirbys to increase base defense, I have seen up to 8 at a port once. no need to up planes any-more to plane field defence.
If you try to up on your own field to defend you get main-gunned at 3-4k by a tank, or blasted from a point forward enemy Wirby shooting straight into runway without penalty by auto-acks.
I still wait for enemy Halftrack with towed 88mm AAA, or Bofors 40mm to show up when I up on a contested friendly field (as on the wish-list)
Using Wirbys to defend a fields should have a max number.
As it stands now Wirbys make low level flying even close to home field looks like an effective suicide attempt.