In World War II, mighty bombers came equipped with gun barrels, manned by gunners at the ready to protect the plane from attacking fighters. The B-52 Stratofortress even came with a tail gun for self defense and last used it in combat over Vietnam in 1972. The change in fighter weapons from guns to missiles made tail guns obsolete, but now Lockheed and DARPA are bringing them back. As freakin’ lasers.