Aircraft carrier

An aircraft carrier is a warship that serves as a seagoing airbase, equipped with a full-length flight deck and hangar facilities for supporting, arming, deploying and recovering shipborne aircraft. Typically it is the capital ship of a fleet (known as a carrier battle group), as it allows a naval force to project seaborne air power far from homeland without depending on local airfields for staging aircraft operations. Since their inception in the early 20th century, aircraft carriers have evolved from wooden vessels used to deploy individual tethered reconnaissance balloons, to nuclear-powered supercarriers that carry dozens of fighters, strike aircraft, military helicopters, AEW&Cs and other types of aircraft such as UCAVs. While heavier fixed-wing aircraft such as airlifters, gunships and bombers have been launched from aircraft carriers, these aircraft do not often land on a carrier due to flight deck limitations.

The aircraft carrier, along with its onboard aircraft and defensive ancillary weapons, is the largest weapon system ever created. By their tactical prowess, mobility, autonomy and the variety of operational means, aircraft carriers are often the centerpiece of modern naval warfare, and have significant diplomatic influence in deterrence, command of the sea and air supremacy. Since the Second World War, the aircraft carrier has replaced the battleship in the role of flagship of a fleet, and largely transformed naval battles from gunfire to beyond-visual-range air strikes. In addition to tactical aptitudes, it has great strategic advantages in that, by sailing in international waters, it does not need to interfere with any territorial sovereignty and thus does not risk diplomatic complications or conflict escalation due to trespassing, and obviates the need for land use authorizations from third-party countries, reduces the times and transit logistics of aircraft and therefore significantly increases the time of availability on the combat zone.

There is no single definition of an "aircraft carrier",^{[citation needed]} 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 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 October 2025, there are 50 active aircraft carriers in the world operated by fifteen navies. The United States has 11 large nuclear-powered CATOBAR fleet carriers – each carrying around 80 fighters – the largest in the world, with the total combined deck space over twice that of all other nations combined. In addition, the US Navy has nine amphibious assault ships used primarily as helicopter carriers, although these also each carry up to 20 vertical/short takeoff and landing (V/STOL) jetfighters and are similar in size to medium-sized fleet carriers. China, the United Kingdom and India each currently operate two STOBAR/STOVL aircraft carriers with ski-jump flight decks, with China in the process to commission a third carrier with catapult capabilities, and France and Russia each operate a single aircraft carrier with a capacity of 30 to 60 fighters. Italy operates two light V/STOL carriers, while Spain,Turkey and Iran operate one V/STOL aircraft-carrying assault ship. Helicopter carriers are also operated by Japan (4, two of which are being converted to operate V/STOL fighters), France (3), Australia (2, previously also owned 3 light carriers), Egypt (2), South Korea (2), China (3), Thailand (1), Brazil (1) and Iran (1). Future aircraft carriers are under construction or in planning by China, France, India, Italy, Russia, South Korea, Turkey and the United States.

Some of the types listed here are not strictly defined as aircraft carriers by some sources.^{[citation needed]}

A fleet carrier is intended to operate with the main fleet and usually provides an offensive capability. These are the largest carriers capable of fast speeds. By comparison, escort carriers were developed to provide defense for convoys of ships. They were smaller and slower with lower numbers of aircraft carried. Most were built from mercantile hulls or, in the case of merchant aircraft carriers, were bulk cargo ships with a flight deck added on top. Light aircraft carriers were fast enough to operate with the main fleet but of smaller size with reduced aircraft capacity.

The Soviet aircraft carrier Admiral Kusnetsov was termed a "heavy aircraft-carrying cruiser". This was primarily a legal construct to avoid the limitations of the Montreux Convention preventing 'aircraft carriers' transiting the Turkish Straits between the Soviet Black Sea bases and the Mediterranean Sea. These ships, while sized in the range of large fleet carriers, were designed to deploy alone or with escorts. In addition to supporting fighter aircraft and helicopters, they provide both strong defensive weaponry and heavy offensive missiles equivalent to a guided-missile cruiser.

Aircraft carriers today are usually divided into the following four categories based on the way that aircraft take off and land: