Like someone stated, everyone want to change the game in their favor.
If you walk down the lane in wishlist forum you can see many things that do just that:
Wirbelwind with no tracers, Bombers that can be used as a triple death-star's on the runway.. etc etc...
What does promote combat, GV vs GV, anti-aircraft vs aircraft, aircraft vs aircraft... main gun vs aircraft ?
My personal view :
If you want to present some sort of realism the main gun vs aircraft must be much harder to accomplish.
No one without any death wish will go one vs one vs a hidden Wirbelwind, when you spot it, you are already dead.
This has become the best way of defending a base, why try to up a plane when a Wirbelwind can do the same feat without even been seen before he press the trigger, vs an aircraft with type @ 6k range icon.
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Yesterday evening Euro TZ we had big map for about 75 players in total, the front line extended to ~15 bases, many in GV's.
My squad with 3 online pilots made one successful attempt to get some flying action.
After the red pilots got shot down, after a good fight - Wirbelwinds replaced the fighters, much owing to the fact that when a pilot see flying action it turn attracts other fighter pilots to join in.
The red planes got simply outnumbered -fully understandably they did take off when their world are full of high potential vulchers.
Often it is a bit too long between the bases to support the field you want to defend.
The above scenario could best be mitigated by support fighter fields (1-3) depending on the map - connected to the main field- not defended by acks, not too far away from the main field- but far enough to give the defenders a chance to take off and get some altitude and defend the airfield.
If the FH get destroyed - no uppers are allowed from either main field or the support fighter fields.
A solution to the Wirbelwind dilemma, denying GV the range to a flying target would make them a bit less effective than they are now.