Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. The XIII Bomber Command is an inactive United States Air Force unit. It was last assigned to Thirteenth Air Force, based at Clark Field, Luzon, Philippines. It was inactivated on 15 March 1946. XIII Bomber Command was a World War II command and control organization for Thirteenth Air Force. Its mission was to provide command and control authority of Army Air Force bombardment organizations within the Thirteenth Air Force Area of Responsibility. The United States Air Force (USAF) is the aerial warfare, space warfare, and cyberwarfare branch of the U.S. armed forces and one of the American uniformed services. Initially part of the United States Army, the USAF was formed as a separate branch of the military on 18 September 1947 under the National Security Act of 1947.