During the Vietnam War the F-4D was used extensively; it served as the principal air superiority fighter for the Air Force, and became important in the ground-attack and aerial reconnaissance roles late in the war. One pilot and one weapon systems officer (WSO) flew this fighter aircraft. The F-4 continued to form a major part of U.S. military air power throughout the 1970s and 1980s. Behind the WSO cockpit you can see the T-33 trainer and F-101 'Voodoo' the NDANG "Happy Hooligans" use to fly.