List of aircraft carrier classes of the United States Navy
On November 14, 1910, pilot Eugene Burton Ely took off in a Curtiss plane from the bow of and later landed a Curtiss Model D on on January 18, 1911. In fiscal year (FY) 1920, Congress approved a conversion of collier into a ship designed for launching and recovering of airplanes at sea—the first aircraft carrier of the United States Navy. More aircraft carriers were approved and built, including , the first class of aircraft carriers in the United States Navy designed and built as aircraft carriers from the keel . The United States declared war on Japan following the attack of December 7, 1941 on Pearl Harbor. The two nations revolutionized naval warfare in the course of the next four years; several of the most important sea battles were fought without either fleet coming within sight of the other. Most of the fleet carriers were built according to prewar designs, but the demand for air protection was so intense that two new classes were developed: light carriers (designated CVL), built on modified cruiser hulls, and escort carriers (CVE), whose main function was to protect Atlantic convoys from German U-boats . During the postwar period, carrier technology made many advances. The angled flight deck was adopted in 1955. The first "supercarrier" was commissioned in 1955 (although an earlier plan had been canceled by the Secretary of Defense), and the first nuclear-powered carrier in 1961, all during the Cold War. Also, a record for crossing the Pacific Ocean was set by a U.S. Navy carrier during the Korean War. Carriers recovered spacecraft after splashdown, including the Mercury-Redstone 3 and Apollo 11 missions. The lead ship of a new class, the , was launched in 2013 and was commissioned in 2017. The  last conventionally powered (non-nuclear) US Navy carrier was decommissioned in 2007. Pre–World War II. On November 14, 1910, a 24‑year‑old civilian pilot, Eugene Burton Ely, took off in a 50 horsepower Curtiss plane from a wooden platform built over the bow of the cruiser ; later, on January 18, 1911, Ely landed a Curtiss Model D on a platform aboard . The Naval Appropriations Act for Fiscal Year 1920 provided funds for the conversion of into a ship designed for the launching and recovery of airplanes at sea—the United States Navy's first aircraft carrier. Renamed , she was commissioned  in 1922. Commander Kenneth Whiting was placed in command. In 1924, "Langley" reported for duty with the Battle Fleet, ending two years as an experimental ship. In 1922, Congress also authorized the conversion of the unfinished battlecruisers and the as permitted under the terms of the Washington Naval Treaty, signed in February 1922. The keel of , the first American ship designed and constructed as an aircraft carrier, was laid down in 1931, and the ship was commissioned in 1934. Following "Ranger" and before the entry of the United States into World War II, four more carriers were commissioned. World War  II. The Imperial Japanese Navy struck Pearl Harbor on December 7, 1941, but none of the Pacific Fleet's aircraft carriers were in the harbor. Because a large fraction of the navy's battleship fleet was put out of commission by the attack, the undamaged aircraft carriers were forced to become the load-bearers of the early part of the war. The first aircraft carrier offensive of the U.S. Navy came on February 1, 1942, when the carriers Enterprise and Yorktown, attacked the Japanese bases in the Marshall and Gilbert Islands. The Battle of the Coral Sea became the first  sea battle in history in which neither opposing fleet saw the other. The Battle of Midway started as a Japanese offensive on Midway Atoll met by an outnumbered U.S. carrier force, and resulted in a U.S. victory. The Battle of Midway was the turning point in the Pacific War. In 1943, new designations for carriers were established, limiting the CV designation to , , and the . The new designations were CVB (Aircraft carrier, large) for the carriers being built, and CVL (Aircraft carriers, small) for the class built on light cruiser hulls. The same directive reclassified escort carriers as combatant ships, and  changed their symbol from ACV to CVE. By the end of the war, the Navy had access to around 100 carriers of varying sizes. On September 2, 1945, Japan signed the surrender agreement aboard , ending World War II. Training ships. During World War II, the United States Navy purchased two Great Lakes side-wheel paddle steamers and converted them into freshwater aircraft carrier training ships. Both vessels were designated with the hull classification symbol IX and lacked hangar decks, elevators or armaments. The role of these ships was for the training of pilots for carrier take-offs and landings. Together  Sable and "Wolverine" trained 17,820 pilots in 116,000 carrier landings. Cold War. Aircraft carrier technology underwent many changes during the Cold War. The first of the 45,000-ton carriers, was commissioned eight days after the end of World War II, on September 10. A larger ship was planned, and in 1948, President Harry Truman approved the construction of a "supercarrier", a 65,000-ton aircraft carrier to be named ; however, the project was canceled in April 1949 by the Secretary of Defense. The Navy's first supercarriers came later, in 1955, with the . 1953 saw the first test of an angled -deck carrier, . The "N" suffix was added to the designation system to represent nuclear powered carriers in 1956. The first carrier to receive this suffix was , commissioned in 1961. The last conventionally powered carrier, , was commissioned in 1968 and was decommissioned in 2007. The Korean War began June 25, 1950, and the need for planes and troops was urgent. Returning from Korea, made a record trip across the Pacific—7 days, 10 hours, and 36 minutes. In 1952, all carriers with designations "CV" or "CVB" were reclassified as attack carriers and given the sign "CVA". As the Mercury-Redstone 3 mission  ended, recovered Commander Alan B. Shepard, the first American in space, on May 5, 1961. Another aircraft carrier , recovered the Apollo 11 astronauts after their splashdown. Apollo 11 was the first manned landing mission to the moon, and was composed of astronauts Neil Armstrong, Buzz Aldrin, and Michael Collins. In 1975, the first was commissioned; the "Nimitz" class are the largest warships in the world; and is the only aircraft carrier class in commission with the U.S. Navy (except for , which, though still technically in commission as of August 2013, is currently being dismantled). Construction and commissioning of the "Nimitz  class continued after the Cold War. Also, in 1975, the U.S. Navy simplified the carrier designations—CV, CVA, CVAN, CVB, CVL—into CV for conventionally powered carriers and CVN for nuclear-powered carriers. After the Cold War. When the Cold War ended in 1991, the U.S. Navy had conventionally powered carriers from the , , and classes active, along with ; and the nuclear and ; however, all of the conventional carriers have been decommissioned. Construction of the Nimitz"-class continued after the Cold War, and the last "Nimitz"-class carrier, , was commissioned in 2009. The next class of supercarriers—the —launched the first ship in  2017. The new carriers will be stealthier, and feature A1B reactors, electromagnetic catapults, advanced arresting gear, reduced crew requirements, and a hull design based upon that of the "Nimitz" class. Ten carriers are planned for the "Gerald R. Ford" class. Escort carriers. During World War II, the U.S. Navy built escort carriers in large numbers for patrol work, and scouting and escorting convoys. Escort carriers, based on merchant ship hulls, were smaller than aircraft carriers; escort carrier crews referred to the ships as "Jeep carriers", the press called them "baby flat tops". The escort carriers had lighter armor than aircraft  carriers, were slower, had less defensive armament, and less aircraft capacity compared to aircraft carriers. This smaller variant of carriers was designated "CVE"; a common joke amongst crews was "CVE" meant "Combustible, Vulnerable and Expendable". Early in the war, German submarines and aircraft were interfering with shipping. The worst losses occurred far at sea—out of the reach of land-based air forces—leading the Royal Navy to experiment with catapult-launching fighter aircraft from merchant ships, a somewhat successful approach. However, the number of planes was still limited, so the United Kingdom appealed to the United States for help . Before World War II started, the U.S. Navy had contemplated converting merchant ships to small aircraft carriers for this purpose, so the quick solution was to build escort carriers on merchant ship hulls. The first escort carrier, , was converted from a freighter. A shortage of merchant ship hulls caused four escort carriers—, , , and —to be built on oil tanker hulls. In total, 78 escort carriers were built and launched from June 1941 to April 1945.