The World's Most Expensive Military Machines Ever Created

7. Aircraft used for aerial refueling: KC-135 Stratotanker

The KC-135 Stratotanker, deployed in 1957 by Boeing, transformed mid-air fuel transfer operations. Its dependable construction enables airborne refueling of numerous aircraft types, expanding mission duration and operational reach. The KC-135's flexibility and durability establish it as a fundamental element of U.S. Air Force missions.