Runways at sea: Evolution of the aircraft carrier

The earliest form of an aircraft carrier was the balloon carrier which was a ship equipped with a balloon, usually tied by a rope or cable, and used for reconnaissance observations.

During the second half of the 19th century and the early 20th century, these ships were built to have the furthest possible view of the surrounding waters. However, they were soon superseded by the development of aircraft carriers at the beginning of World War I.

An aircraft carrier is a warship that serves as a seagoing airbase, equipped with a flight deck and hangar facilities for supporting, arming, deploying and recovering shipborne aircraft.

The aircraft carrier is the capital ship of a fleet known as a carrier battle group that includes support ships such as cruisers, destroyers and frigates.

It allows a naval force to project seaborne air power far from its homeland without depending on local airfields for staging aircraft operations.

Since its inception in the early 20th century, aircraft carriers have evolved from wooden vessels to nuclear-powered supercarriers that carry dozens of fighters, strike aircraft, military helicopters, airborne early warning, control aircraft and other types of aircraft such as unmanned combat aerial vehicles.

The aircraft carrier, along with its onboard aircraft and defensive ancillary weapons, is the largest weapon system ever created.

By its tactical prowess, mobility, autonomy and the variety of operational capabilities, aircraft carriers are often the centrepiece of modern naval warfare.

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, carriers have great strategic advantages in that, by sailing in international waters, it does not need to interfere with any territorial sovereignty and does not risk diplomatic complications or conflict escalation due to trespassing.

Aircraft carriers obviate the need for land use authorisations from third-party countries, reduce the times and transit logistics of aircraft and therefore significantly increase the time of availability on the combat zone.

Aircraft carriers have significant diplomatic influence in deterrence, command of the sea and air supremacy.

The US normally positions aircraft carrier groups in "hot spots" such as in the Mediterranean and Red Seas due to the Israeli/Hamas and the Russian/Ukraine wars.

As of December 2024, there are 47 active aircraft carriers in the world operated by 14 navies. The US has 11 large nuclear-powered catapult-assisted take-off but arrested recovery (CATOBAR ) fleet carriers. Each carries around 80 fighters with the total 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.

The US currently operates two classes of aircraft carriers: the Nimitz class, the world’s second-largest aircraft carrier, and the Gerald R Ford class, the largest class in the world.

China, the UK and India each currently operate short take-off, barrier-arrested recovery (STOB) and short take-off and vertical landing aircraft (STOVL) carriers with ski-jump flight decks.

The Indian navy has two aircraft carriers in active service, one of which is the INS Vikrant which was the first indigenously built carrier in India.

China is in the process of commissioning 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 and Spain operates one V/STOL aircraft-carrying assault ship.

As "runways at sea," aircraft carriers have a flat-top flight deck, which launches and recovers aircraft. Aircraft are launched forward into the wind and are recovered from astern.

The flight deck is where the most noticeable differences between a carrier and a land runway are found. Creating such a surface at sea poses constraints on the carrier. For example, the size of the vessel is a fundamental limitation on runway length. This affects take-off procedures, as a shorter runway length of the deck requires that aircraft to accelerate more quickly to gain lift. This requires a thrust boost using a catapult.

An aircraft catapult is a device used to help fixed-wing aircraft gain enough airspeed and lift for takeoff from a limited distance, typically from aircraft carrier flight decks.

The catapult used on aircraft carriers consists of a track or slot built into the flight deck, below which is a large steam-operated piston that is attached through the track to the nose gear of the aircraft.

At launch, a release bar holds the aircraft in place. When steam pressure builds up to the required level, the bar releases freeing the piston to pull the aircraft along the deck at high speed. Within about two to four seconds, the aircraft velocity by the action of the catapult plus apparent wind speed is sufficient to allow an aircraft to safely fly away.

The island on an aircraft carrier is the command centre for the ship and flight deck operations. It's a building on top of the flight deck that's usually around 150 feet tall and 20 feet wide at the base.

The island's top is equipped with radar and communications antennas

The most advanced aircraft carrier in the world is the nuclear-powered USS Gerald R Ford.

The US navy intends to eventually acquire ten of the USS Gerald R Ford-class aircraft carriers to replace current carriers on a one-for-one basis.

A major difference is that the new class of aircraft carriers have the electromagnetic aircraft launch system (EMALS). The EMALS system launches carrier-based aircraft using a catapult employing a linear induction motor rather than the conventional steam piston, providing greater precision and faster recharge compared to steam.

EMALS’s main advantage is that it accelerates aircraft more smoothly, putting less stress on their airframes.

EMALS can launch both heavier and lighter aircraft than a steam piston-driven system.

Aircraft carriers are operated by Australia, Brazil, China, France, India, Italy, Japan, Russia, Spain, South Korea, Thailand, Turkey, the UK and US.

Henry Kissinger, former US Secretary of State, once said: "An aircraft carrier is 100,000 tons of diplomacy."