AV-8B Harrier II

The Boeing AV-8B Harrier II is a STOL ( Short Take Off and Landing)/VTOL (Vertical Take Off and Landing) fighter jet used by the United States Marine Corps, as well as the Italian and Spanish navies. It appears in Call of Duty 4: Modern Warfare and Call of Duty: Modern Warfare 2. The Harrier is used by the USMC to support their amphibious landing operations. They usually carry out airstrikes against enemy fortifications and units in support of friendlies. As a VTOL aircraft, it is capable of hovering in place like a helicopter, though it mostly relies on its speed to avoid enemy fire. It is slower than most attack fighters, which is why it is more useful in a Ground Support role.

Call of Duty 4: Modern Warfare
A flight of USMC AV-8B Harrier IIs appear in the mission Heat, callsign Falcon One. They provide close air support to the S.A.S. team using cluster bombs. Additionally the player can see Harriers bombing targets in the mission Shock and Awe ahead of the Marine assault, thereby reducing resistance to a ground assault by the Marines. Two of the jets fly right over the player's position in the mission Charlie Don't Surf when they are on the roof of the TV station.

Campaign
The Harrier II also makes a handful of appearances in Campaign, though they are seen far less often than in Call of Duty 4, with the F-15 Eagle replacing them in the role of Close-Air Support. A pair of them can be seen showing off their VTOL capability in the level Exodus.

Multiplayer
The Harrier strike is an unlockable killstreak reward in Call of Duty: Modern Warfare 2. Requiring a killstreak of 7, or 6 with the Hardline perk, the Harrier Airstrike calls in three harrier jets. Two bomb the target location, and the third hovers in place over the selected area, and will attempt to kill enemy targets with its undermounted gun. The third jet will also fire missiles at an enemy Attack Helicopter, Pave Lows, or Chopper Gunner if seen in the air and destroy them.

Unlike Pave Low, Harrier kills from both the airstrike and strafing runs extend the user's killstreak. This makes the Harrier very useful for achieving higher ranked killstreaks such as Chopper Gunner or AC130.

Trivia

 * If a player gets the game-winning killcam with a Harrier, they will unlock the title True Liar, a reference to the movie True Lies. Although, if they get the game winning killcam with the air strike part, they will instead be rewarded with Afterburner.
 * The Harrier Strike is an inaccurate representation of the AV-8B's abilities. Harriers are not designed to use their vector thrust nozzles to hover over an area for extended periods of time, only for take off and landing. While hovering, the Harrier uses immense amounts of fuel, and is very difficult to maneuver.
 * If an enemy attack craft appears on the screen, all friendly Harriers will attack and most likely destroy it, going as far as to launch missiles at it.
 * Harrier Strikes are often preferred over attack helicopters because of the addition of the short bombing run at the beginning of the killstreak.
 * Harriers are often considered easier to destroy than Attack Helicopters, as they hover in one spot and do not move very much.
 * Destroying a Harrier rewards you with 300 XP, or sometimes 400 if destroyed with an LMG or SMG.
 * The Airstrike portion of the killstreak reward is actually treated as a Precision Airstrike. For example, if a game-winning kill is scored with the bombing portion instead of the Harrier itself, you will complete the challenge of getting a game-winning kill with a Precision Airstrike instead of a Harrier strike.
 * The Harrier Strike is inaccurate in another way because for the aircraft to hover it has to use large amounts of water (stored internally) to cool the engine since no air is going through the engine. Because of this it can only hover for about a minute at a time, before the engine overheats.
 * In the level Exodus it is inaccurate that the Harrier is taking off in VTOL configuration since when it is fully loaded for close air support it is too heavy to take off vertically, and would use the STOL configuration or Short Take Off and Landing.
 * If two Harrier Strikes are called in at roughly the same time in the same place, the two hovering supports may fly through each other. If you or an enemy destroys the two glitched harriers, you can be rewarded with over 1000 EXP, as you get 400 for each, 800, and then another few for getting a 'double kill' and for destroying the two supports so quickly. Occasionally, a Pave Low may make a pass nearby, and it seems that any low-flying support can no-clip into the same spot.
 * Most people consider the Harrier Strike is just like the Precision Airstrike, with the addition of a hovering Harrier. However, this is untrue. With a Precision Airstrike, you can choose the direction, in which the bombers will bomb in a line. The Harrier attacks a single location, somewhat like a Predator Missile.
 * The Harrier will not release flares when shot at by a launcher.
 * The Harrier in the events of Modern Warfare 2 should have long been replaced by the F-35B.