Question Mark (aircraft) Question Mark (aircraft) Question Mark (""?"") was a modified Atlantic-Fokker C-2A transport airplane of the United States Army Air Corps. In 1929, commanded by Major Carl A. Spaatz, it was flown for a flight endurance record as part of an experiment with aerial refueling. "Question Mark" established new world records in aviation for sustained flight (heavier-than-air), refueled flight, sustained flight (lighter-than-air), and distance between January 1 and January 7, 1929, in a non-stop flight of more than 150 hours near Los Angeles, California. Following the record-setting demonstration, the C-2A was returned to transport duties. In 1931 more powerful engines replaced
Vogt Lo-150 United States. A.J. Smith won the US Nationals flying an Lo-150 in 1961. Harold Jensen flew an Lo-150 in 1962, winning the Barringer Trophy. Vogt Lo-150 The Vogt Lo-150 is a West German high-wing, single seat glider that was designed by Alfred Vogt and produced by the Wolf Hirth Company. The Lo-150 was developed from the wing span aerobatic Vogt Lo-100 as a performance cross country sailplane. The Lo-150 is constructed from wood, including its wooden monocoque fuselage. Its span two-piece wing employs a Clark Y airfoil and incorporates flaps for glidepath control. Early examples use a take-off dolly and