20th Air Force patch.

20th Air Force patch, original, WW2.

Established on 4 April 1944 at Washington D.C, 20 AF was a United States Army Air Forces combat air force deployed to the Pacific Theater of World War II. Operating initially from bases in India and staging through bases in China, 20 AF conducted strategic bombardment of the Japanese Home Islands. It relocated to the Mariana Islands in late 1944, and continued the strategic bombardment campaign against Japan until the Japanese capitulation in August 1945. The 20 AF 509th Composite Group conducted the atomic attacks on Hiroshima and Nagasaki in August 1945, and remains as the only air force organization to have used a nuclear weapon in combat.