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
Islamic Republic of Iran Army Aviation as in breaking the Siege of Paveh) and Kordestan provinces. The Iran–Iraq War saw the most intensive use of helicopters in a conventional conflict ever. IRIAA flew more than 300,000 hours in direct support of the operations throughout the war, in addition to around 59,000 hours in training sorties, with an average of 100 hours recorded flight per day overall during the war. During the initial months of the war, the Army Aviation, usually operating on its own and using intelligence from local people, managed to stop Iraqi tanks from further advancing into the western territories of Iran. This was