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
The Airplane Factory Sling 4 The Airplane Factory Sling 4 The Sling 4 is a development of the Sling 2 to accommodate four people, built by The Airplane Factory of Johannesburg, South Africa. The Sling 4 is an all-metal, low-wing, fixed tricycle gear homebuilt aircraft. The aircraft was developed in 2009. The canopy was modified to include gull-wing doors. The aircraft features flaps with 40 degrees of travel. In July 2013 a Sling 4 was flown by Mike Blyth and his son from South Africa to AirVenture in Oshkosh, Wisconsin, United States. The flight included a 14-hour over-water leg. The aircraft carried 20 hours endurance