Cheap Tankers by the Dozen !
The Boeing KC-135 Stratotanker is an aerial refueling military aircraft. It and the Boeing 707 airliner were developed from the Boeing 367-80 prototype. The KC-135 was the US Air Force's first jet powered refueling tanker and replaced the KC-97 Stratotanker. The Stratotanker was initially tasked to refuel strategic bombers, but was used extensively in the Vietnam War and later conflicts such as Desert Storm to extend the range and endurance of Air Force, Navy and Marine tactical fighters and bombers.
Serving with the United States Air Force since 1957, it is one of just six military fixed wing aircraft with over 50 years of continuous service with its original operator. Supplemented by the larger KC-10, complete replacement is still under study by the Air Force. Despite increased maintenance costs, studies conclude many of the aircraft could be flown until 2040, with ages reaching 80 years before reaching lifetime flying hour limits. Seen at the Davis-Monthan Air Force Base, in Tuscon AZ