Below Radar should be removed from the game. It gives too much of a benefit to air players. Why do they get magic flares, with a reload that's only 2 seconds longer than the stinger reload, with nerfed AA vehicle guns that overheat almost instantly and take forever to reload, a nerfed static AA gun (which is almost always in a completely useless location), and then on top of that, get a magic altitude level where they suddenly can't be locked on. It's madness.
If I asked for infantry players to get a magic "below sniper" where if I'm closer than 75 meters they do no damage, or "below RPG" in a tank where if I'm within 50 meters of an engineer player their RPG's can't hurt me, I'd be laughed at. But air players get this protection despite being the fastest units on the map and being able to fly high enough that nothing can hit them before they decide where to attack. No-one else in the game gets that.
The AA tank needs it's gun significantly buffed. It's impossible to get a kill unless a dumb pilot flies in circles around you for 30 seconds while it waits for you to reload the AA gun multiple times. It's range is pathetic, and is shorter than the air vehicles weapons. The jet can bomb you with missiles from longer range than you can shoot back as one example. Why is a vehicle designed to shoot it's entire load of ammunition in one burst if required, so nerfed and slow to shoot and turn the turret?