sentences:  The ship delivered the 506th to Guam on 17 March, and a week later the pilots flew their new P-51D-20s to Tinian.There they would stay for seven weeks, flying combat air patrols and practice missions while the field engineers on Iwo Jima prepared North Field for them at the northern end of the island.The group was assigned to Twentieth Air Force, which, in turn, attached the unit to VII Fighter Command 301st Fighter Wing.