United States Army Air Force Heavy Bomber Units, E.T.O. and M.T.O. 1942-45

On 11 June 1942, twelve U.S. Army Air Force B-24D Liberators dropped 36,000 lbs of bombs on the oil refinery complex at Ploesti, Rumania, in the first American heavy bomber attack of World War II. Although damage to the target was slight, the mission was a significant portent of things to come -henceforth, the middle years of the war would see the US strategic bombing effort directed at the defeat of Nazi Germany, a policy outlined before Pearl Harbour. The Japanese attack meant diversion of some men and machines to the Pacific, but the 'Europe first' plan remained in being. A primary element of that plan was to establish a long-range bomber force in the British Isles to attack continental Europe and, by the time of the Ploesti mission, the first combat units had begun to move to England.
In April 1941 the Army Special Observer Group, headed by Maj. Gen. James E. Chaney, was estab­lished in London to prepare for the possible involvement of US air and ground forces in the European war. With British leaders, this group carried out the necessary groundwork to set up a heavy bomber command, which would be super­vised by Maj. Gen. Carl Spaatz, chosen for the task by Gen. H. H. Arnold, commanding general of the AAF. To head the new command, Spaatz selected Brig. Gen. Ira C. Eaker, an officer with widespread military experience and a reputation for diplomacy.