World War I
Since the advent of powered, heavier-than-air flight in the early 20th century, modern militaries have sought to engineer a way to deploy and recover aircraft from seaborne vessels. Catapult-launched seaplane carriers were the earliest ships that could be defined as aircraft carriers, but the development of the true prototype to the modern aircraft carrier came in 1910-1911 with the first successful efforts of American Eugune Ely in taking off and landing from a flattop vessel. His historical landing on the U.S.S.Pennsylvania utilized an improvised braking system of sandbags and ropes that latched onto an arresting wire on the plane – a system, in essence, that is still used today with jet aircraft. The HMS Ark Royal, launched in 1914, was arguably the first modern aircraft carrier and saw service in the Gallipoli campaign in World War I. During this period, the role of carrier-based aircraft was often limited to reconnaissance and attempts to employ torpedoes and other anti-ship weaponry were met with limited success, hindered by the physical limitations of the aircraft at the time.
World War II
The intermission between the World Wars saw a number of design improvements in carrier design. HMS Argus was the first aircraft carrier with a full-length, flat flight deck, while the HMS Hermes featured the addition of the starboard control tower still used in modern aircraft carriers. The United States Navy also entertained an airborne aircraft carrier in the 1930s with the helium airships Akron and Macon, complete with internal hangars and a “trapeze” mechanism that could launch and recover their Curtiss F9C Sparrowhawk biplane fighters, until the Akron was destroyed in a disastrous thunderstorm off the New Jersey Coast in 1933.
During World War II, technological advances in military aviation drove the transition in naval combat doctrine from battleships being the dominant force to aircraft carriers (see A Brief History of Aerial Warfare). On December 7th, 1941, the Imperial Japanese Navy fielded an unprecedented aircraft complement of six fleet carriers to attack the American naval base of Pearl Harbor, demonstrating the force projection now possible with a modern navy and bringing the United States into the war in earnest. Fortuitously, the American aircraft carriers were not in port at the time of the attack, and the battleships of the Pacific Fleet were the main casualties of Pearl Harbor. The Battle of the Coral Sea, fought from May 4 – 8, 1942 between the U.S.S. Yorktown, the U.S.S. Lexington, and the Japanese fleet carriers Shōkaku and Zuikaku, marked the first naval action in history where two opposing forces engaged in combat without ever being in visual range of each other, as well as the first engagement of two opposing carrier groups. The importance of the aircraft carrier was so significant that Japan’s defeat in the Pacific Theatre can be directly attributed to the loss of four fleet carriers in 1942 during the decisive Battle of Midway and their subsequent inability to match the United States’ industrial output of aircraft carriers. On June 19 – 20 1944, the remainder of Japan’s carrier operating strength was eliminated during the Battle of the Philippine Sea, where the Imperial Japanese Navy lost the vast majority of their carrier air group strength in the largest carrier-versus-carrier action in naval history – an impetus for their kamikaze attacks in the closing stages of the war.
The Cold War and Beyond
The development of the jet engine near the end of World War II necessitated a further progression in carrier design – fundamentally, these were the same problems of launching and safely recovering aircraft, but at much higher speeds with planes of higher weight. in the early 1950s, the British introduced the concept of the angled flight deck, where the runway is tilted at approximately 10 degrees from the longitudinal axis of the ship. This was a safety feature that allowed take off and landing to occur along a slightly orthogonal axis to aircraft that were parked or taxiing. Steam-powered catapults (which were attempted in the earliest iterations of carrier design, before the introduction of the flat-top ship) and ski jump ramps were also new developments in the 50s, permitting jet aircraft to take off with a much shorter length of runway. In regards to landing, arrestor hook technology was improved with the introduction of a pneumatic deceleration system that would slow the aircraft more smoothly and more powerfully. Night landings were also a challenging problem on a moving ship in unpredictable ocean conditions – innovative optical landing systems that utilized a gyroscopic mirror or light source to orient the pilot to his angle of approach were welcome improvements over the the use of manual flag signals from the flight crew on deck. Aircraft carriers served as forward operating bases and air support platforms for many major wars in the 21st and latter half of the 20th centuries, though there would be no further engagements of two opposing carrier groups after World War II.
Modern day aircraft carriers are essentially floating cities, with their nuclear reactors capable of operating without refueling for up to 20 years. Their global presence and capability for force projection are central to United States military doctrine, and the location of carrier battlegroups at any given moment plays a key role in decision-making during times of crisis. Despite the disproportionate strength of the United States Navy carrier fleet to the rest of the world (10 operational carriers, with every other country having between 0-2), there is some speculation that increasingly advanced anti-ship missile technology may render aircraft carriers obsolete in the future. A paradigm shift from a large, expensive fleet of supercarriers to a more numerous fleet of smaller vessels that can all function as light carriers may alleviate the risk of anti-ship ballistic missiles. Indeed, many United States Navy ships, from light amphibious assault ships to destroyers to newer oil tanker models, can act as aircraft carriers to varying degrees. The disadvantages to this approach are that smaller gas-powered ships are less armored, slower, and have a significantly reduced range. Cruise missile-equipped nuclear submarines are also an alternative option to replace or augment the role of the supercarrier in global force projection, and one that is comparably less expensive and vulnerable to enemy attack.