USS Wasp (CV-7) was a United States Navy aircraft carrier commissioned in 1940 and lost in action in 1942. She was the eighth ship named USS Wasp, and the sole ship of a class built to use up the remaining tonnage allowed to the U.S. for aircraft carriers under the treaties of the time. As a reduced-size version of the Yorktown-class aircraft carrier hull, Wasp was more vulnerable than other United States aircraft carriers available at the opening of hostilities. Wasp was initially employed in the Atlantic campaign, where Axis naval forces were perceived as less capable of inflicting decisive damage. After supporting the occupation of Iceland in 1941, Wasp joined the British Home Fleet in April 1942 and twice ferried British fighter aircraft to Malta.

Wasp was then transferred to the Pacific in June 1942 to replace losses at the battles of Coral Sea and Midway. After supporting the invasion of Guadalcanal, Wasp was hit by three torpedoes from Japanese submarine I-19 on 15 September 1942. The resulting damage set off several explosions, destroyed her water-mains and knocked out the ship's power. As a result, her damage-control teams were unable to contain the ensuing fires that blazed out of control. She was abandoned and scuttled by torpedoes fired from USS Lansdowne later that evening. Her wreck was found in early 2019.

An aircraft carrier is a warship that serves as a seagoing airbase, equipped with a full-length flight deck and facilities for carrying, arming, deploying, and recovering aircraft. Typically, it is the capital ship of a fleet, as it allows a naval force to project air power worldwide without depending on local bases for staging aircraft operations. Carriers have evolved since their inception in the early twentieth century from wooden vessels used to deploy balloons to nuclear-powered warships that carry numerous fighters, strike aircraft, helicopters, and other types of aircraft. While heavier aircraft such as fixed-wing gunships and bombers have been launched from aircraft carriers, one has yet to successfully land on one. By its diplomatic and tactical power, its mobility, its autonomy and the variety of its means, the aircraft carrier is often the centerpiece of modern combat fleets. Tactically or even strategically, it replaced the battleship in the role of flagship of a fleet. One of its great advantages is that, by sailing in international waters, it does not interfere with any territorial sovereignty and thus obviates the need for overflight authorizations from third-party countries, reduces the times and transit distances of aircraft and therefore significantly increase the time of availability on the combat zone.

There is no single definition of an "aircraft carrier", and modern navies use several variants of the type. These variants are sometimes categorized as sub-types of aircraft carriers, and sometimes as distinct types of naval aviation-capable ships. Aircraft carriers may be classified according to the type of aircraft they carry and their operational assignments. Admiral Sir Mark Stanhope, RN, former First Sea Lord (head) of the Royal Navy, has said, "To put it simply, countries that aspire to strategic international influence have aircraft carriers." Henry Kissinger, while United States Secretary of State, also said: "An aircraft carrier is 100,000 tons of diplomacy."

As of March 2022, there are 47 active aircraft carriers in the world operated by fourteen navies. The United States Navy has 11 large nuclear-powered fleet carriers—carrying around 80 fighters each—the largest carriers in the world; the total combined deck space is over twice that of all other nations combined. As well as the aircraft carrier fleet, the US Navy has nine amphibious assault ships used primarily for helicopters, although these also each carry up to 20 vertical or short take-off and landing (V/STOL) fighter jets and are similar in size to medium-sized fleet carriers. The United Kingdom and China each operate two aircraft carriers. France, India, and Russia each operate a single aircraft carrier with a capacity of 30 to 60 fighter jets. Italy operates two light fleet carriers and Spain operates one. Helicopter carriers are operated by Japan (4, two of which are being converted to operate V/STOL fighters), France (3), Australia (2), Egypt (2), South Korea (2), China (2), Thailand (1) and Brazil (1). Future aircraft carriers are under construction or in planning by Brazil, China, France, India, Russia, South Korea, Turkey and the US.