It takes at least 3 to take down a chopper....it is fine.
Stop being a *....
1st off let me say that i'm an infantry player that enjoys playing against vehicles but only when it's fun and rewarding for all.
With so many players the air assets are going to be under the pump, while ground units can get some choice in how much contact they can have using cover air doesn't get that ability as much with maps so open.
Also for infantry it's unrewarding to hit air units with the recoilless and not get insta-kills on the mid range vehicles and the AA takes too long to lock on compared to the pace of this game.
So i suggest a couple of things for balance.
1, All air units except the bigger transport choppers are 1 hit recoilless and the transports are 2 hit
2, Lower the baseline AA lock on time by about 1/3(wait....look at point 3 before rage)
3, INCREASE lock on time based on the vehicles direction change and speed. Movement in programming is based on a vector(3 sets of numbers in a 3d game) so have those values add to the lock on time(in a balanced proportion) that would make max speed in a straight line increase lock on time by .5 and change in direction by 2 to 2.5.
4, Make lock on time increase by 3 if below say.... 30m above terrain height by default(i think it's usually a perk in most bf games but in this one it feels kinda necessary)
5, Give attack choppers and transport an extra set of flares by default.
That way compared to what we have now you've made hovering vehicles easy kills, vehicles moving to location roughly 25% longer lock on, vehicles trying to dodge AA at low altitude up to 5x longer lock on, heavier vehicles because of the slower speeds get slightly shorter lock on times but extra flares.
As a side note i'd also increase splash damage of the weapons on infantry by about 2x but decrease the splash area by 1/2, at the moment it feels like the damage is really low but the area effect really spammy. More precise aim should be rewarded.
