Flight deck in the context of "Naval aviation"

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.

This is a list of aircraft carriers which are currently in service, under maintenance or refit, in reserve, under construction, or being updated. An aircraft carrier is a warship with a full-length flight deck, hangar and facilities for arming, deploying, and recovering aircraft. The list only refers to the status of the ship, not availability or condition of an air wing. This includes helicopter carriers and also amphibious assault ships, if the vessel's primary purpose is to carry, arm, deploy, and recover aircraft.

An aircraft catapult is an acceleration device used to help fixed-wing aircraft reach liftoff speed (V_LOF) faster during takeoff, typically when trying to take off from a very short runway, as otherwise the aircraft engines alone cannot get the aircraft to sufficient airspeed quickly enough for the wings to generate the lift needed to sustain flight. Launching via catapults enables aircraft that typically are only capable of conventional takeoffs, especially heavier aircraft with significant payloads, to perform short takeoffs from the roll distances of light aircraft. Catapults are usually used on the deck of a ship — such as the flight deck of an aircraft carrier — as a form of assisted takeoff for navalised aircraft, but can also be installed on land-based runways, although this is rare.

Historically it was most common for seaplanes (which have pontoons instead of wheeled landing gears and thus cannot utilize runways) to be catapulted from ships onto nearby water for takeoff, allowing them to conduct aerial reconnaissance missions and be crane-hoisted back on board during retrieval, although by the late First World War their roles are largely supplanted by the more versatile biplanes that can take off and land on carrier decks unassisted. During the Second World War before the advent of escort carriers, monoplane fighter aircraft (notably the Hawker Hurricane) would sometimes be catapulted from "catapult-equipped merchant" (CAM) vessels for one-way sorties to repel enemy aircraft harassing shipping lanes, forcing the returning pilot to either divert to a land-based airstrip, jump out by parachute, or ditch in the water near the convoy and wait for rescue. By the time fleet carriers became the norm in WW2, catapult launches have become largely unnecessary and carrier-based fighter-bombers would routinely perform self-powered takeoffs and landings off and onto carrier decks, especially during the naval aviation-dominated Pacific War between the United States and the Empire of Japan. However, escalating arms races during the Cold War accelerated the adoption of the heavier jet aircraft for naval operations, thus motivating the development of new catapult systems, especially after the popularization of angled flight decks further limited the practical distance available as takeoff runways. Nowadays, jet aircraft can launch from aircraft carriers via either catapults or ski-jump deck, and perform optics-assisted landing onto the same ship with help from decelerative arresting gears.

A navalised aircraft (or navalized aircraft) is an aircraft that is designed for naval usage. A navalised aircraft specifically designed to take off and land from the flight deck of an aircraft carrier is called a carrier-based aircraft.

Navalised aircraft include both fixed-wing (including seaplanes, biplanes, monoplanes and flying wings, both propeller- and jet-propelled) and rotary-wing aircraft (helicopters, tiltrotors and, in some cases, multicopters). In many cases, the aircraft is simply a modified variant of a land-based model. They are different to land-based aircraft in that they are designed to tolerate greater corrosion due to humidity and salt weathering around marine environments, handle increased mechanical stress due to harsher air conditions such as strong sea breezes and extreme weathers, and often need to operate on moving vessels at sea, which typically dictates more complex flight control to deal with unsteady sea state and also the ability to perform vertical/short takeoff and landing as there are very limited runway spaces available (or none at all) on deck.

A carrier-based aircraft (also known as carrier-capable aircraft, carrier-borne aircraft, carrier aircraft or aeronaval aircraft) is a navalised aircraft designed for seaborne flight operations from aircraft carriers. The term is generally applied only to shipborne fixed-wing aircraft that require a runway of some sort for takeoff and landing, as VTOL aircraft such as helicopters are inherently capable of adapting to flight operations from a wide variety of ships (not just aircraft carriers) as long as the served vessel is equipped with helipads or a sufficiently spacious deck that can provide a reliable landing area, which include helicopter carriers, amphibious assault ships, aviation-capable surface combatants (cruisers, destroyers, frigates and some corvettes), container ships and even cruiseliners.

Carrier-based aircraft are designed for many purposes including aerial combat, surface attack, anti-submarine warfare (ASW), search and rescue (SAR), carrier onboard delivery (COD), weather observation, reconnaissance and airborne early warning and control (AEW&C). Such aircraft must be able to take off from the short distance available on the carrier's flight deck and be sturdy enough to withstand the abrupt forces exerted by on a pitching deck due to sea waves. Some modern carrier aircraft are designed for catapult-assisted takeoffs and thus also need to be constructed more robust airframes and landing gears that can handle sudden forward accelerations. Arrestor hook is mandatory feature for those designed for CATOBAR or STOBAR landing, while thrust vectoring or tiltrotor nacelles are commonly seen in those capable of V/STOL operations. In addition, their wings are generally larger (thus can generate more lift) than the land-launched counterparts, and are typically able to fold up or swing back for taxiing, pushback and parking in tight quarters.

An electromagnetic catapult is a type of aircraft catapult that uses a linear induction motor system rather than the single-acting pneumatic cylinder (piston) system in conventional steam catapults. The system is used on aircraft carriers to launch fixed-wing carrier-based aircraft, employing the principles of electromagnetism and Lorentz force to accelerate and assist their takeoff from the shorter flight deck runways. Currently, only the United States and China have successfully developed electromagnetic catapults, which are installed on the Gerald R. Ford-class aircraft carriers (currently only the lead ship CVN-78 being operational), the Type 003 aircraft carrier Fujian and the upcoming Type 076 amphibious assault ship Sichuan (51).

Electromagnetic catapults have several advantages over their older, superheated steam-based counterparts. Electromagnetic operation recharges via electric energy and thus much faster than the pressurization process of steam systems, and does not suffer power loss with distance (where volume expansion within the steam catapult cylinder proportionally reduces pressure), temperature changes (which directly affects pressure according to ideal gas law) and leakages (which matters in pressure vessels but is irrelevant in electromagnet systems). The electromagnetic acceleration is also more uniform (unlike steam acceleration, whose accelerative force is always highest at the very initial phase, thus creating a distinct "jolt"), therefore reducing the stress upon the airframe considerably, resulting in increased safety and endurance as well as lower maintenance costs for the aircraft. Electromagnetic catapults are configurable and can assign varying power outputs to different sections, thus allowing them to tailor optimal acceleration to individual aircraft according to different payload weights and takeoff behaviours. Electromagnetic systems are more compact and also weigh less, have fewer linkage components and thus are expected to cost less and require less maintenance, and also require no fresh water boiling for their operation, thus reducing the need for energy-intensive desalination and sophisticated piping systems used in steam catapults, which take up significantly more space below the flight deck.

In aviation, a ski-jump is an upwardly curved ramp that allows a fixed-wing aircraft to take off from a runway that is shorter than the aircraft's conventional takeoff requires. By providing an upward vector from the ski-jump's normal force, the aircraft is launched at an elevated angle and lift-off can be achieved at a lower airspeed than that required for flat takeoff, as it allows the aircraft more airborne time after leaving the runway to continue accelerating until enough airspeed has been reached to sustain flight. Ski-jumps are commonly used to launch shipborne aircraft from flight decks of aircraft carriers that lack catapults.

It is believed that the first use of the ski-jump occurred during the Second World War, when a temporary ramp was added to HMS Furious to help heavily laden Fairey Barracudas attack the German battleship Tirpitz. During the Cold War, the concept was studied as a means of reducing the length of flight decks required for aircraft carriers and to facilitate ever-heavier aircraft at sea. The Royal Navy took a particular interest in the ski-jump during the 1970s, conducting tests with the new Hawker Siddeley Harrier VSTOL fighter, then added a ramp to its next generation of aircraft carrier, the Invincible class.

A helicopter carrier is a type of aircraft carrier whose primary purpose is to operate helicopters. It has a large flight deck that occupies a substantial part of the deck, which can extend the full length of the ship like HMS Ocean of the Royal Navy (RN), or extend only partway, usually aft, as in the Soviet Navy's Moskva class or in the Chinese Navy's Type 0891A. It often also has a hangar deck for the storage and maintenance of rotorwing aircraft.

Pure helicopter carriers are difficult to define in the 21st century. The advent of STOVL aircraft such as the Harrier jump jet, and now the F-35B, have complicated the classification; the United States Navy's Wasp class, for instance, carries six to eight Harriers as well as over 20 helicopters. Only smaller carriers unable to operate the Harrier, and older, pre-Harrier-era carriers, can be regarded as true helicopter carriers. In many cases, other carriers, able to operate STOVL aircraft, are classified as "light aircraft carriers". Other vessels, such as the Wasp class, are also capable of embarking troops such as marines and landing them ashore; they are classified as landing helicopter docks.