1942 sparked an idea to build an aircraft carrier whose size would be limited only by the dock dimensions. In late 1942, work on Project X1 commenced—a ship with a displacement of 56,800 tons. The main disputes arose around the hangar, as previous ships were built with an entirely closed hangar. However, the U.S. aircraft carriers operating experience showed that its necessary to warm up aircraft engines in the hangar to carry out a massive launch of the air group. The choice fell on a project with an open hangar and two aircraft lifts on the port side. All works were stopped with the end of World War II.