Yeah the map sizes are too small for the current MANPAD ranges and abilities. It makes airpower obsolete with current settings. Lock-on weapons need a nerf.
Things I'd like considered for Aircraft:
Jets - be unlockable with MANPADS when at high altitude, but vulnerable at low altitude such as when doing an attack run. AAA missiles should also be restricted in range, but further than MANPADs.
Helicopters - ducking behind cover(Masking)/low altitude flying should break MANPAD locks, just like they do with aircraft lock-on weapons. This is when AAA or RPG weapons should be used.
Jets/Helicopters - need more room to breathe on these maps. As soon as you lift-off the runway, you get locked from MANPAD or AAA across the tiny map. Enemy Air defense envelopes go beyond the boundaries of the maps, so there's no escape. Jets/Helicopters should have the ability to "loiter" at extended ranges, plan attacks and roll-in. This is when they should become vulnerable to enemy Air Defense.
MANPADs/JAVELINs should be automatically spotted (just like firing guns without a silencer/flash hider) after launch, and for an extended period (10-15 seconds). Make it vulnerable to use them.
Carrying these lock-on weapons should reduce movement speed significantly (like LMG). Make it vulnerable to use them.
Increase ammo quantities, but remove infinite ammo. Require Helicopters to Return to base for re-arming. This prevents helicopters from terrorizing entire matches. Having them fall back to re-arm balances their power.
These are just some thoughts since playing with the Jets and Helicopters...
