An Attack Helicopter is a combat-dedicated helicopter. Many attack helicopters are two-seat, with a gunner and a pilot, and are armored against small arms fire. Though capable of air-to-air combat against other helicopters, they are not intended to take on the faster and more agile fixed-wing aircraft, and as such are mostly relegated to a ground-attack role, and to fit that role are built like mobile weapons platforms; most modern attack helicopters have a nose-mounted vulcan cannon or autocannon, rocket pods, guided missiles, and occasionally other armaments.
The first dedicated attack helicopter was the AH-1 Cobra being introduced in 1967 for the United States Army, until being gradually replaced by the newer, modern, AH-64 Apache. Since then, many other nations have adopted their own attack helicopters such as the Mi-28 Havoc and Ka-52. Compared to their cousins, the transport helicopters, they are most often uni-rotor (compared to the many dual-rotor transport helicopters devised) and are usually lighter and more agile.
In-game, helicopters fulfill the same role as in real life. Most helicopters in the games are armored against ground fire (in the earlier games to a much lesser extent). They are usually more agile than transport helicopters, and are usually armed with several weapons.