Did you know a pickup lets you carry like 10 stingers?

At 900$ a pop, even if it takes 2-3 to take down a heli you usually break even interrupting their supply lines, and they can never really find you since you're always on the move in one of the fastest vehicles. A lot cheaper than setting up an AA base they can raid. The best tip I can provide, is that 90% of heli pilots only carry two flares, and they WILL pop them before returning to base. You can bait a lot of pilots to flare to empty on their way to the CZ without actually firing a stinger, which results in free kills as they try to come back home.