Lieutenant General Carl Spaatz, the previous NAAF, 12th Air Force, and 8th Air Force commander, took over the new United States Strategic Air Forces (USSTAF) consisting of Doolittle's 8th Air Force and Twining's 15th Air Force. This allowed Spaatz to borrow the 15th in Italy for long-range strategic bombing of European targets when inclement weather in England prevented the 8th from flying missions. Under this scenario, some heavy bombers took off from Italy, bombed German targets, and landed in England.see also Shuttle bombing Similarly, some flew the opposite route. Overnight stops in Russia were also made by some of the long-range bombers of the 8th and 15th Air Forces.
