And while most of these aircraft remain concepts or test prototypes, the Argentine Pucara saw combat use in the Falklands conflict. One trend in dedicated tankers is toward converted wide body airliners, since they can usually dispense about 135,000kg of fuel with spare space for cargo or passengers. There are, however, several platforms available, and the recent Japanese search for tanker aircraft illustrates this wide range options. Contingency tankers are fighter or attack aircraft carrying the maximum extra fuel and a refueling pod. Contingency tankers are most commonly used deep in hostile airspace where the threat to dedicated tankers is too great.
Tankers disseminate their goods either through a telescopic boom or a hose and drogue system.
The boom is positioned by an operator on board the tanker into a receptacle on top of the receiving aircraft. When using the hose and drogue system, the receiving aircraft maneuvers its probe into the brogue trailing the tanker. The boom was developed by the US Air Force during SAC's hey day. Its advantage over the hose and drogue system is its massive fuel transfer rate. The KC10A, for example can dispense 5680 liters per minute through its boom and only 2270 liters per minute from the hose and drogue system.