Aircraft carriers have two basic configurations. The most common has a flat top deck that serves as a take-off and landing area for airplanes. A steam-powered catapult accelerates an aircraft under full throttle, from 0 to 165 mph in 2 seconds during take-off to help it reach take-off speed. To land on the carrier, incoming airplanes moving at 150 mph are equipped with tailhooks to engage one of up to four arresting cables stretched across the deck, stopping the aircraft within 320 feet after engaging a cable.
The second configuration, most commonly used by the Royal Navy, has a 'ski-jump' at one end of the flat deck, that helps launch the aircraft. This arrangement is designed for use with VTOL or STOVL aircraft that are able to take off and land with little or no forward movement. These aircraft do not require catapult facilities or arrestor cables to be deployed across the flight deck.
In either case the ship steams at up to 30 knots (56 km/h) straight into the wind during take-off and landing operations in order to increase the apparent wind speed, thereby reducing the required speed of the plane relative to the ship).
Aircraft carriers are generally accompanied by a number of other ships, to provide protection for the relatively unwieldy carrier, to carry supplies, and to provide additional offensive capabilities. This is often termed a battle group or carrier group, sometimes a carrier battle group.
Cruisers and other ships of the early twentieth century often carried a few catapult launched seaplanes that could be recovered by crane after landing on the water. These planes were often used for reconnaissance. Many modern warships have helicopter landing capability and helicopter assault ships represent a new form of aircraft carriers.
The first strike from a carrier against a land target took place on July 19, 1918. Seven Sopwith Camels launched from HMS Furious[?] attacked the German Zeppelin base at Tondern[?]. Several airships and balloons were destroyed.
The first ship to have a full length flat deck was HMS Argus[?] the conversion of which was completed in September 1918. The first ship to be designed specifically as an aircraft carrier was the second HMS Hermes which was commissioned in July 1923.
Aircraft carriers played a large role in World War II including the Japanese attack on Pearl Harbor. The Battle of Midway where 4 Japanese carriers were sunk by planes from 3 American carriers is often considered the turning point of the war in the Pacific.
More modern uses of aircraft carriers include the Falklands War, where the United Kingdom was able to win a conflict some 8,000 miles from home in large part due to the use of the carriers HMS Hermes and HMS Invincible. The US has also made use of carriers in the Persian Gulf and to protect its interests in the Pacific.