"I gather you've disposed of that Gunship, Dr. Freeman. Your reputation, sir, is well deserved."
―Odessa Cubbage

The Combine Gunship, often simply referred to as Gunship, is a powerful, autonomous, Combine Synth aircraft that combines aspects of an airplane and a helicopter with Synth technology.

Gunships are powered by an array of different jet engines on their underside, and maneuver using a rear helicopter-like rotor with insect wing-like blades. Compound eyes that bear a close resemblance to those of a dragonfly are positioned directly behind the Gunship's pulse gun, and are thought to aim the weapon. In addition, the chassis itself has one large exposed compound eye on either side, which is assumed to be used to detect enemies under normal conditions. Like most Combine Synths and vehicles, the gunship is invulnerable to small arms fire and can only be damaged by heavy weapons, such as rocket-propelled grenades. Because of this weakness to explosives, gunships will give any incoming explosives a priority over enemies and will attempt to shoot them down.

Although lacking the Hunter-Chopper's explosive mines and rockets, the gunship surpasses its aerial counterpart in maneuverability and accuracy with its pulse turret.

The gunship is generally deployed to attack enemies not normally accessible to ground forces, due to their dangerous actions or in remote locations where air power would be more convenient. In urban environments or when protecting highly important facilities (such as the Citadel dark fusion reactor, Nova Prospekt's outter defense or the Overwatch Nexus) Gunships are deployed in what appears to be a buddy system, in which one Gunship protects the other from missile attacks. However, when deployed to oversee vast spaces (such as the coast) they are deployed only one unit at a time.

Destroying a gunship with the RPG requires a unique strategy. Since gunships concentrate their fire on any incoming missile and attempt to shoot them down, the laser designator should be used to guide the missile in unpredictable loops and rolls on its way to the target, to make it as difficult as possible for the gunship to hit the missile. Ideally, perform evasive maneuvers with the missile until it gets close, then steer it around the gunship and hit it from behind. It is also sometimes possible to fire straight up at a gunship directly above the player and hit its belly before it has time to recognize the threat.

Gunships are one of the toughest enemies, and dealing with them presents a number of problems, doubly so if there are other enemies in the vicinity at the same time (or, worse, multiple gunships, they cover each other). Since it takes at least three hits (depending on difficulty) to destroy one, the player can only effectively fight one if they have a steady source of replacement ammunition for the RPG. Its also important to have plenty of overhead cover to use in between firing at the gunship, because whenever the player doesn't have a missile in the air, it'll be firing at them.

Gunships will always prioritize missile over any other target, so if the player has, for example, one missile left and needs to get across open ground to resupply, just fire the missile into the air and steer it around as long as possible while moving to the next spot of cover. The gunships will be completely distracted by the missile, allowing the player to get to safety and/or resupply.

The Combine Dropship, often simply referred to as Dropship, is a Synth used by the Combine to quickly send units by air to areas they are needed.

Dropships are very useful aircraft for the Combine, being able to quickly transport Combine Soldiers, APCs, Striders, and Civil Protection officers to where ever they may be needed. Dropships are also seen dropping Rollermines along the coast, making it evident that the Combine also use them as minelayers. The Scout Car was also taken away by a Dropship at the end of the battle lead at Lighthouse Point.
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http://half-life.wikia.com/wiki/Combi...
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