Well, here's the thing. As Pugwipe said, the heli's and planes CAN be modified to drop bombs. In single player there is a few missions that do just that.
A simple game for the heli's would be to have an arena. All over this arena have a bunch of exploding barrels, maybe diffrent colors (say red for 5 points, blue for 10, and yellow for 15). Each player has a set ammount of bombs they can drop, and must return to the starting point to pick up new bombs. The red barrels would be closest, blue a little further, and yellow the furthest. (maybe even change those barrels to the tanks that you guys hate so much

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All this is VERY possible. In one of the single player mission you have to get your tank (which drives along the road by itself) to the other side. In its way are road blocks. You as the heli driver have to blow up these road blocks up, and return to the starting point to pick up new bombs each time.
EDIT:I almost forgot. You also have to pick up small bridges and place them over rivers for your tank to cross!
As for the tanks, they CAN be slowed down. I agree they are very fast, and since they don't shoot anything, they are pretty much worthless (unless you have a game that blows them up

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My question is, could the RC planes be retrofitted with the guns from the Rustler (the spitfire look-a-like plane that shoots machine guns)???? That would make for an awsome minigame as those RC planes arent the easiest thing to fly.