AS the only designated AA we have sucks, we need them.
These would be cap points on the map which can be capped like any other ground point. but once activated will shoot down aircraft that get to close firing special AA versions of the tow (150 impact +150 explosive.) it fires 3 missiles per volley with 8 seconds between volleys. Forcing copters that want to be in the area to either shoot down the missiles or deploy flares.
These would be placed in key points and would make ground a major part of the mode other then just claiming kills. as they can dictate where your teams air can go safely.