 Although the Sixth Army's 37th Infantry Division declared that Clark Field and Fort Stotsenburg had been "liberated" on 31 January 1945, remnants of Japanese forces hiding in the Zambales foothills west of the field could still do some damage.Clark Field remained an Army Air Base until May 1949, when its facilities were transferred to the U.S. Air Force.Prior to this a build-up of aircraft, air wings and maintenance facilities were already being staged at Clark.