The U.S. Air Force (and the U.S. Congress) has agreed to lease 100 KC-767 aircraft from the manufacturer for six years starting in 2006. This will cost  $138 million per aircraft ($23 million a year). This deal gets the aircraft into use three years earlier than if they were bought (damn lawyers again) The initiative also includes a provision to purchase the aircraft for about $4 billion at the end of the lease in 2017, for a total cost of about $300 million per aircraft. The KC-767 is a two engine aircraft with a maximum weight of 179 tons and can carry 96 tons of fuel. The KC-767 is equipped to refuel Air Force, Navy, Marine and allied aircraft day and night. It can transfer 20 percent more fuel than the 43 year old KC-135E aircraft. The KC-135, derived from the B-29, was adapted to civilian use as the Boeing 707. But 707 production ceased in 1991. So any new tankers will have to be based on some other aircraft. As a tanker, the 767 still has it's main cabin available for either passengers or cargo. Of course, weight of anything in the main cabin is deducted from the maximum fuel load carried. The pumps and other equipment for refueling is located below the main cabin, where cargo containers are normally carried. In 2001, Italy ordered four Boeing 767 commercial aircraft configured as a tanker.