‘The Flying Memorial,’ a Vietnam-era helicopter visits the Iowa State Fair. The YL-37 helicopter served during the Vietnam War from 1965 to 1968. According to The YL-37 Group Foundation, the group behind the flying museum, it is the only Marine UH-34D Sikorsky helicopter with documented combat history that survived the war. Now, it serves as a flying memorial to honor Vietnam veterans, and as a hands-on educational tool to teach the newer generations about the war. YL-37 served with the HMM-362