The rear of the refueler is equipped with a boom that has limited maneuverability, which allows it to dock with the receiving aircraft's fuel tank. Locking the boom and nozzles in place completes an electrical circuit that starts the pressurized pumping of the fuel.

In-flight refueling, or aerial refueling, is a complex maneuver involving a tanker aircraft and a receiver aircraft, primarily using one of two systems: the Flying Boom or the Probe-and-Drogue. The "Flying Boom" system, used mostly by the U.S. Air Force, features a rigid, telescoping tube at the back of the tanker that is physically "flown" by a dedicated boom operator into a receptacle on the receiver plane. This method allows for extremely high fuel transfer rates, often up to 6,000 lbs per minute. The "Probe-and-Drogue" system, favored by the Navy and many international air forces, involves a flexible hose trailing from the tanker with a funnel-shaped "basket" (the drogue) at the end. The pilot of the receiver aircraft must maneuver a retractable probe on their nose or wing into this basket to initiate the fuel flow. While the probe-and-drogue is slower, it allows a single tanker to refuel multiple small aircraft simultaneously. Both methods require precise formation flying, with the two aircraft typically flying just 35 to 80 feet apart at high speeds.