Project cost: $52 billion
FY 2013 estimate: $1.8 billion
Mid-air refueling isn’t just a fantasy of "Dr. Strangelove,” “Air Force One” and “The West Wing” screenwriters. It’s a real and very costly way to top off a tank. KC-46A tankers can take off at up to 207.5 tons and can transfer 103.8 tons of fuel to other aircraft, using a refueling boom and “pods” on their wings, according to the Air Force’s website. Boeing is developing the newest tanker, estimated to cost $187 million apiece, using its 767 commercial airliner. The KC-46A’s first flight is scheduled for late 2014.