AF-1 hot pit refuels during its second flight. In hot pit refueling, the pilot stays in the cockpit and the aircraft remains on the ground and running as it is refueled. Lockheed Martin test pilot Jeff Knowles is the pilot for the mission (which counts as one flight). The overall flight lasts 2.3 hours. This is the first time hot pit refueling is used to fly back-to-back missions with the F-35.
