In the United States Air Force, as well as with the US Marine Corps, US Navy, and most allied air forces, pilots, and especially fighter pilots, are commissioned officers. They are expected to make important decisions, sometimes with incomplete information, that the military reserves for officers. The notable exception is US Army helicopter pilots, who are not always commissioned officers, as they can be warrant officers. As commissioned officers, military pilots’ pay follows a fairly rigid pay structure that is based on duration of service and rank.