Learning Pearl Harbor: What Is an Aircraft Carrier?

USS Enterprise (CV-6), USS Lexington (CV-2), USS Saratoga (CV-3). Looking through the list of ships that were moored at Pearl Harbor on December 7, 1941—and it's a long list of battleships, cruisers, destroyers, repair ships, and others—you’ll find that these three vessels were elsewhere that morning. These three US Navy vessels were powerful aircraft carriers, and while they weren’t present at Pearl Harbor at the time of the assault, their names often come up in various “What If…” scenarios.

What if the three aircraft carriers had been in port at Pearl Harbor during the attack? What if only one or two had made it back in time to intercept Japan’s aerial strike force? While there are different theories as to what might have happened had any or all of the aircraft carriers been in the harbor that morning, more relevant questions to ask may be, "What is an aircraft carrier, and what difference did their absence make to the outcome of the attack?”

What Is an Aircraft Carrier?

IJN planes aboard Shokaku preparing to attack Pearl Harbor

At the time of the US entry into World War II, the US Navy had just seven aircraft carriers in its ranks. By the end of the conflict, there were over 160. As the name implies, aircraft carriers are large warships that are responsible for launching warplanes at sea. Aircraft carriers were essentially mobile, floating air bases.

Their large, flat decks were used for planes to take off and land, providing the ability to launch aircraft far away from a land-based airstrip. It was because of aircraft carriers that Japan was able to launch its attack on Pearl Harbor successfully. Without them, there would have been no way the Imperial Japanese Navy’s planes could have made the more than 4,000-mile journey across the Pacific.

The First Aircraft Carriers

The history of the aircraft carrier begins long before Pearl Harbor and World War II, though. The large vessels' origins kick off in the early 20th century, with the introduction of the first fixed-wing aircraft, which was flown by the Wright Brothers at Kitty Hawk, North Carolina.

Ely taking off from USS Birmingham November 14, 1910

Within a few short years of that successful flight, a former auto salesman named Eugene Burton Ely, became the first man to launch a plane from the deck of a US Navy ship.

His take-off, on November 14, 1910, was off the deck of the cruiser USS Birmingham (CS-2). Within two months, Ely made another first, this time landing his Curtiss plane aboard the armored cruiser USS Pennsylvania (ACR-4). Both of his feats were successful, and soon garnered attention from overseas when, in 1912, the British Royal Navy also launched its first airplane from a ship.

In what's considered the first ship-based air raid, in 1914 the Imperial Japanese Navy ship Wakamiya launched a Farman aircraft against the Austro-Hungarian cruiser Kaiserin Elisabeth and the German gunboat Jaguar.

Four years after this accomplishment, HMS Argus of the British Royal Navy became the world’s first carrier that could launch and recover aircraft. Early aircraft carriers were typically conversions of cargo ships, cruisers, battleships, and battlecruisers, mostly because the Washington Naval Treaty of 1922 limited the construction of new surface combat vessels.

Among the first conversions for the United States Navy were the Lexington-class carriers. For Japan, it was Akagi, one of the carriers responsible for the attack on Pearl Harbor. Both of these had originally been laid down as battlecruisers. By the mid-1920s, ongoing evolution of the carriers led to the construction of ships designed and built specifically as aircraft carriers.

The Aircraft Carrier and World War II

HMS Illustrious

When war came again, the aircraft carrier became a major part of naval operations, and had an significant impact on the conduct of the Second World War. Aerial combat was a major factor throughout the worldwide conflict, and aircraft carriers provided a base for these attack runs. Especially in the Pacific, where much of the war was fought on the sea, carriers played a large role in combat.

One of the first examples of the power and importance of the aircraft carrier came in 1940, when HMS Illustrious of the Royal Navy carried out a strike against the Italian Fleet from a range that would otherwise have been impossible. The US Navy showed off the capabilities of its carriers during the Doolittle Raid, the “revenge” strike against Tokyo in April of 1942.

Despite their versatility in combat, aircraft carriers also proved to be vulnerable compared to other traditional warships. The importance of the carrier led to the design of the so-called light carriers, a smaller but quicker-to-build version of the standard aircraft carrier. For the United States, the USS Independence (CVL-22) was an example of a light carrier that was converted from the hull of a cruiser.

Aircraft Carriers and the Modern Navy

After World War II, nations started seeing an increase in size of standard aircraft, which also meant that aircraft carriers would have to become larger. The Nimitz-class carriers were known for having a displacement four times that of the USS Enterprise.

Modern carriers are notorious for their cost, forcing navies to carefully analyze whether they’re necessary during armed conflict or even present in potential hot spots. Aircraft carriers of today are considered as capital ships of a nation’s fleet. The largest  of these are the Supercarriers, some of which are powered by nuclear reactors.

Despite the vast improvements, carriers are still vulnerable to attack due to their lack of firepower. For carriers to move safely in international waters, they’re accompanied by an escort of various warships in what’s called a carrier battle group.

USS Gerald R. Ford (CVN-78)

The United States Navy currently operates 20 aircraft carriers, making up just under half of the total carriers in service worldwide. While the Nimitz-class carrier is the current standard, it is being followed by the Gerald R. Ford-class carrier, which will be more automated, reducing the amount of manpower needed to maintain and operate them. The new class will also incorporate a new Electromagnetic Aircraft Launch System and carry unmanned aerial craft. These larger ships, with a displacement close to 100,000 tons, are expected to cost upwards of $14.5 billion.