Spaatz was the US General commanding Air Forces in Europe and the Pacific. Spaatz was an official observer in London during the Battle of Britain. In July 1942 he arrived in London again as Commander of the 8th Air Force, which was to be the principal arm of the strategic air offensive against Germany. He favored day-time precision bombing which brought him into conflict with the British Air Staff which had opted for night-time area bombing. He set the 8th Air Force campaign on its way and was then sent to the North African Theater to co-ordinate air operations of Eastern Air Command and the 12th Air Force. He then became Commander of the Northwest Africa Air Force during the Tunisian campaign and later in Sicily. In January 1944 he returned to Britain as Commanding General of the Strategic Air Force, whose campaign in northern Europe was now in full swing. He directed the aerial preparation of the Normandy landings and then switched to the destruction of the synthetic oil plants, followed by the transportation system within Germany itself. By March 1945, when Spaatz left Europe, production of oil and movement of inland transport in the Reich had been almost completely halted. In July he took command of the Strategic Air Force in the Pacific and directed the bombing of Japan’s major cities. His planes also carried the atom bombs which fell on Hiroshima and Nagasaki.