By May 1942, Los Alamitos was operating with a complete physical plant including administrative office, sick bay, a synthetic training facility, central files, classroom, and an assembly & repair department. With a station complement of about 2,500 officers and men, the initial aviation cadets began their training. The first graduating class numbered 729 cadets, 180 having washed out. By the end of the year, the base's 36 planes had increased to 140, and in 1943, five outlying fields were acquired, Training was carried out mostly in plywood planes. When changed from the command of the Naval Primary Training Command to that of Naval Air Center, Eleventh Naval District, on 15 August 1943, it was used to station carrier air groups. Renamed a naval air station, its flight operations were conducted by a Fleet Air Detachment, with station complement dropping from about 250 officers and 2000 men to 40 officers and 500 men and the Assembly and Repair Department discontinued but still used by the CASU on board. Many CASUs and ARGUSs (groups to establish forward air bases) were formed at and dispatched from Los Alamitos during the war. With additional construction undertaken after mid-1943, the total investment at the station to 1 January 1945 was $4,827,014.64. Growing from one officer, one man, and one plane in 1928, Los Alamitos in 1945 had become one of the Navy's most important air stations.