Aircraft carriers were designed in the years between
World War I and
World War II.
Flight decks were installed on several different types of ships to explore the possibilities of operating naval aircraft without the performance limitations of flotation devices required for
seaplanes and
flying boats. The most successful of these early aircraft carriers were built from
battlecruisers. Battlecruisers typically had a speed of about , which was several knots faster than the speed of contemporary
battleships. Additional speed was not necessary for maintaining station with the battle fleet, but enabled the carrier to catch up with the battle fleet after temporarily leaving formation to turn into the wind for
launch or recovery of aircraft. The speed of the carrier during launch effectively decreased the takeoff distance for embarked aircraft, so faster carriers could operate heavier aircraft with greater range and superior combat capability. As such naval aircraft became operational, no nation could risk fielding less capable aircraft; so the speed of later purpose-designed aircraft carriers was set by the speed of the converted battle cruisers. The
Washington Naval Treaty of 1922 limited the displacement of purpose-designed aircraft carriers to 23,000 tons. The idea of a modern fleet carrier was developed in 1931 by Admirals
J.J. Clark and
Harry E. Yarnell of the
United States Navy. Fleet carriers, instead of operating as scouts for the fleet, would operate in unison with the fleet, to ward off air attacks and to strike opposing forces from the air. Cruisers and destroyers would protect fleet carriers. The fleet carriers would then displace battleships as the preeminent assets of the surface fleet. A fleet carrier would carry more than 50 aircraft, and be fast enough to keep up with other major elements of the fleet, such as cruisers and battleships. As combat experience demonstrated the importance of aircraft carriers, numerous ships were rapidly converted to operate aircraft during World War II; and it became important to differentiate ships with the speed and size allowed by the Washington Naval Treaty from ships that were slower and/or carried fewer aircraft. Ships of similar speed carrying fewer aircraft were identified as light aircraft carriers (CVL) and ships of lower speed became known as escort aircraft carriers (CVE).
Fleet aircraft carrier became the term to distinguish front-line aircraft carriers from the generic description of any warship carrying aircraft. In the post-war era, the United States Navy sought to give aircraft carriers a strategic bombing capability in addition to their tactical role. The largest bombs carried by carrier aircraft during the Second World War had been about but experience had indicated some hardened targets like
submarine pens were impervious to bombs of less than . The fleet carriers of World War II were incapable of operating meaningful numbers of aircraft large enough to carry such heavy bombs over anticipated distances with performance characteristics to avoid defending aircraft. The term fleet carrier then evolved to differentiate the
supercarriers designed for strategic bombing roles from the older fleet carriers delegated limited tactical roles like
anti-submarine (CVS) or
amphibious warfare (LPH). ==Comparison of World War II fleet carriers==