When playing a LAN or Internet game, get into an airplane and instruct your friends to get onto the plane's wings. Get them to Crouch down, hold down the walk button and slowly walk forward when the plane is in motion, so that they don't fall off. Fly them over the enemy's territory, or more effectively, a crucial control point and tell them to let go of the buttons, and press jump (so that they don't hit the back wings) then parachute down to the ground safely and engage. Your friends can also attack shortly after putting their parachute up, so get them all to drop their grenades on the enemy, clearing their landing point.

This tactic is very effective at flanking or surrounding the enemy.