Helicopter

Helicopters are flying machines that unlike airplanes, do not have to be moving forward in order to remain airborne. They can both remain stationary in one place and rotate in place as well. However, they are not as fast as more conventional aircraft.

In Multiplayer
In Multiplayer, a helicopter can be summoned to aid your team when a 7-kill-streak (Killing 7 enemies without dying) has been a been achieved. Once summoned, the Helicopter will fly around the map, in a random pattern, firing on any enemies it can with it's heavy machine guns. This is very useful for taking racking up additional kills, and for making the opposing team distracted.

The Helicopter will leave after 2 minutes on the battlefield, but it can leave earlier if it is shot down. Shooting down a helicopter is no easy task, though, and the only weapons that are relatively effective against it are the RPG and the M60 Light Machine Gun. And even a hit from an RPG alone will not bring down a Helicopter, but it will severely damage it.

Helicopters also fire missiles and rockets in multiplayer, but these never hit anything, and are probably only put into the game for visual purposes.