How Does an Aircraft Carrier Work? Flight Deck, Catapults and Nuclear Power

What an aircraft carrier is

An aircraft carrier is a warship built around an idea that’s simple to state and hard to pull off: carry a runway out to the middle of the ocean so aircraft can take off and land from it. Since World War II, aircraft carriers have become among the most important warships in the world’s navies, able to project air power to any point on the oceans without relying on a nearby land base.

The first ship to manage this with a full-length flight deck, unbroken from bow to stern, was the British HMS Argus. In one of naval history’s odder twists, it started out as an Italian ocean liner: the Royal Navy bought it in 1916, converted it, and completed it as an aircraft carrier in September 1918, with a flight deck about 170 meters long and a hangar that could hold 20 aircraft. It became the prototype for every carrier that followed.

From steam power to the nuclear reactor

For decades, aircraft carriers stayed on conventional propulsion, cluttered with fuel bunkers, smokestacks and exhaust ducts that ate up valuable space. On September 24, 1960, the USS Enterprise was launched, the first nuclear-powered aircraft carrier in the world, entering service the following year. With eight reactors driving its four propellers, a displacement of about 75,000 tons and a flight deck over 330 meters long, the Enterprise managed to sail more than 320,000 kilometers over three years without stopping to refuel.

Starting in 1975, the ten carriers of the Nimitz class took the Enterprise’s place, proving that carriers didn’t need nearly as much nuclear power to match its performance: they get by on just two reactors, against the Enterprise’s eight, while reaching comparable speeds, and their uranium core lasts about 13 years between refuelings. The newest carriers, like the USS Gerald R. Ford, build on the Nimitz’s basic hull while betting on a new generation of launch and recovery systems, which we’ll get to shortly.

What happens on the flight deck

The operational heart of an aircraft carrier is the flight deck, and on a Nimitz-class ship it’s a rectangle about 77 meters wide where, within a few dozen seconds, a fighter jet can go from a standstill to airborne, or from 240 km/h to a dead stop. Two separate systems make that violent acceleration or deceleration possible.

The steam catapult takes a 37-ton fighter jet from zero to 180 miles per hour, about 290 km/h, in under three seconds, using less than 300 feet, about 91 meters, of available deck: an acceleration that, in physical terms, isn’t so different from what shows up in any basic lesson on force, mass and acceleration, just applied on an industrial scale. The arresting wires do the opposite job: they stop a landing aircraft arriving at 150 miles per hour, about 240 km/h, within less than 400 feet, catching it with steel cables about 5 cm thick connected to hydraulic rams below deck.

Practical example: landing on an aircraft carrier is a bit like trying to park a car going full speed into a space the size of a couple of parking spots, then stopping it dead with a hook bolted to the bumper. The pilot aims to catch one of the four wires stretched across the deck; miss them all, and the pilot has to power back up and try again, a maneuver called a “bolter.”

Below the flight deck, elevators connect the surface to the hangar underneath, where aircraft are parked, repaired and refueled before heading back up. A Nimitz-class carrier has four of them, and the ship can hold up to 85 aircraft in total, though the air wing actually embarked during real operations tends to be smaller.

The flight deck’s color code

With dozens of aircraft, vehicles and people moving through a cramped, loud and potentially dangerous space, a coordination mistake can be costly. That’s why the flight deck runs on a system of seven jersey colors that identify roles at a glance, according to the US Department of Defense’s official service DVIDS: yellow directs aircraft and keeps personnel safe; blue operates the elevators and drives the tractors that move aircraft around; purple handles fast, safe fueling; white covers safety, medical staff and landing signal officers; green maintains the arresting gear and catapults; brown belongs to the technicians assigned to individual aircraft; red handles munitions and doubles as the crash and fire crew. As one flight-deck safety specialist told DVIDS, the system helps everyone working there understand in an instant who needs to be where.

It’s not an isolated case of coordinating a chaotic space through simple rules: systems like this echo, on a much smaller scale, how a flight data recorder on an airliner has to work reliably and predictably even in the most extreme conditions, with no room for improvisation.

CATOBAR versus STOVL: two ways to fly

Not every aircraft carrier is built the same way. There are two main design families, and the difference comes down mostly to the kind of aircraft the ship needs to carry.

	CATOBAR (e.g. Nimitz, Ford)	STOVL (e.g. Italian Cavour)
Takeoff	Steam or electromagnetic catapult	Ski-jump ramp, 12° on the Cavour
Landing	Arresting wires	Short or vertical, no wires
Aircraft carried	Conventional fixed-wing fighters	Short-takeoff/vertical-landing jets, like the F-35B
Typical displacement	About 97,000 t at full load	About 27,100 t at full load
Propulsion	Nuclear	Conventional, gas turbines

The Cavour, flagship of Italy’s Carrier Strike Group, is an example of a STOVL carrier: 244 meters long, with a flight deck measuring 220 by 34 meters, it displaces 27,100 tons at full load and carries up to 20-22 aircraft, a mix of EH-101 helicopters and AV-8B or F-35B jets depending on the mission. Its crew numbers 1,210, including the flight component and an embarked marine brigade. It isn’t only a carrier: it also doubles as a logistics platform, command post and hospital ship, much the way smaller STOVL carriers often carry helicopters alongside their jets, a reminder that not every deck launch is a catapult shot — some of it looks closer to how a helicopter’s rotor generates lift than to a fighter blasting off a Nimitz.

US nuclear carriers, at the opposite extreme, remain the exception rather than the global rule: the scale of a Nimitz, nearly 97,000 tons and a combined crew of over 5,600 people, isn’t the model most of the world’s navies, including those of other wealthy nations, are trying to match.

The new electromagnetic catapults

On the newest carriers, like the USS Gerald R. Ford, the old steam catapults give way to EMALS, an electromagnetic launch system. According to the US Navy’s NAVAIR command, electromagnetic catapults can accelerate aircraft to takeoff speed more smoothly than the old steam catapults, cutting down on airframe stress, and can be tuned more precisely to an aircraft’s weight: an advantage that also helps with launching drones, which are far lighter than a crewed fighter jet.

Working alongside EMALS is AAG, Advanced Arresting Gear, the landing system that replaces the older Mk-7. NAVAIR describes it as a modular system built from energy absorbers, control electronics and digital systems, designed to safely stop a much wider range of aircraft than before, from the lightest unmanned drones to the heaviest crewed fighters. AAG is already installed on the USS Gerald R. Ford, and it’s also planned for the future USS John F. Kennedy and USS Enterprise, the second ship to carry that name after the nuclear pioneer of 1961.

A myth worth busting

The movie image of the aircraft carrier as an unsinkable fortress, impossible to hit and impossible to stop, doesn’t hold up well against the US Navy’s own professional debate. A deployed carrier, that discussion argues, can be more exposed than commonly assumed to a so-called “mission kill”: the loss of the ship’s operational capability, for example its flight deck or launch systems, without the ship actually sinking. Modern carriers put more weight on redundant critical systems and the ability to keep operating under pressure than on the thick armor of an old-style battleship, the kind that dominated naval warfare before World War II: they remain complex targets to defend, one reason they almost always sail with an escort of other ships, not invulnerable fortresses sailing alone.