Here's a crazy glitch I've been messing around with. Get a tank and enter the flying cheat (Right, R2, Circle, R1, L2, down, L1, R1). Now go to a straight stretch of road. Turn the turret 180 degrees (backwards) by using the right analog stick. Now start driving and blasting your turret and you will eventually lift off the ground. Keep shooting and you can stay in the air and fly anywhere you want, like inside the stadium. It's reallly hard to control in the air, I almost always stall and flip over