Glenn Liston retiring after 37 years of service to the Air Force, Department of Defense
Glenn Liston, chief of the U.S. Air Force Research Laboratory High Speed Experimentation Branch at Arnold Air Force Base, stands by a model of the X-51A WaveRider, an experimental, scramjet-powered hypersonic vehicle. In addition to his other career milestones, Liston said he is most proud of his involvement in the development of the aircraft. He will be retiring from Air Force civilian service June 30 after 37 years of federal service. (U.S. Air Force photo by Deidre Ortiz)