[Imp]

AAA defence tricks & tips including gamey options most of which you only need if the game is rich in enemy air.

AAA guns vs fast air probably leave as is so get a few shots at it but vs helos reduce range to improve hit chance. Helo may well also end up in range for multiple on target shots in your turn.
Only units I often micro manage.

MANPADs if you have quite a few turn some off you only need 1 hit to stop the plane coming back not several to take it down.
Don't move them if airs coming in they need the stationary firer flag enabled for max effect.

Verus attack helos if they end there turn in a good position for shots next turn if possible attack them to force them to move & hence attack with lower accuracy.

Protecting high value assets.
Likes of MBTs switch AA off in opfire filter or turn off the MG, they wont give away there position or use there shots for AA leaving none for when a ground target comes into view.
Any/all of the following, best vs strafing runs but still effective vs standoff weapons
Move them in an unexpected way, i.e temporary retreat so they are not where the planes looking.
Try not to have them out front or alone.
Screen by having cheaper units like APCs near them.
Don't move or fire them if your expecting incoming air next turn & they are not in enemy LOS, you could however move the cheaper units mentioned above so they are easily visible to the planes & hopefully get targeted instead.
Don't forget good old smoke to hamper targeting.

Its basically another layer to combined arms you try not to get caught in an armour infantry arty combined attack by avoiding or removing so spend a few turns engaging or being hit by the air while you are NOT engaging other enemy units because that's when it really hurts.
Don't worry about giving up ground if you have to & moving towards your AAA.

Really gamey tactic
Versus helos if your in trouble & especially if you have fast AA capable APCs pull back so they come ahead of enemy lines then go kamikaze.
Like some people do with cheap helos
Run furthest APCs to draw fire then run others adjacent for a half decent hit chance & open up.
Worst case you will force it to run & use weapons on low value targets.
Best Helo is damaged or dead for less points lost than its worth.

Then there is helo on helo battles if you have some.