Jan. 1-7, 1929. In an era when America was already "endurance conscious" because of marathon dancers and flagpole sitters, the Air Corps set a world flight endurance record of 150 hrs, 40 mins, 14 sec. A Fokker C-2A named the Question Mark took off from Metropolitan Airport at Van Nuys, Cal. on Jan. 1, 1929, circled over Southern California while being refueled 42 times (9 at night), and landed on Jan. 7 when one of its engines failed. Because of their unreliability at this early period, no radios were installed in the Question Mark or the two refueling Douglas C-1s.

Communications were maintained by notes dropped to the ground and by hand signals, flashlight signals, ground panels, and messages written on blackboards carried in the planes. Since it was not practical to transfer oil for the engines by hose, cans of oil were lowered to the Question Mark by rope, as were food, water, and other supplies.

This flight was of great value to the Air Corps. It thoroughly tested the reliability of the plane, its engines, and its accessories, and the effects of continuous flight upon its crew members. It also had an impact upon civilian aviation, for it triggered a rash of civilian endurance flights which focused an even greater public attention upon aviation.