Before the attack on Pearl Harbor and during the period within which the predecessor U.S. Army Air Corps became the Army Air Forces in late June 1941, President Franklin D. Roosevelt gave command of the Navy to an aviator, Admiral Ernest King, with a mandate for an aviation-oriented war in the Pacific. FDR allowed King to build up land-based naval and Marine aviation, and seize control of the long-range bombers used in antisubmarine patrols in the Atlantic. At the same time, the Boeing B-17 Flying Fortress was developed, which would later play a large role in World War II. Come World War II, General Henry H. Arnold became head of the AAF. One of the first military men to fly, and the youngest colonel in World War I, he selected for the most important combat commands men who were ten years younger than their Army counterparts, including Ira Eaker, Jimmy Doolittle, Hoyt Vandenberg, Elwood "Pete" Queseda, and, Curtis LeMay. However, since the AAF was not yet its own military branch, it was left out of some major decisions of the war.