Recent financial reports from U.S. aircraft manufacturer Northrop Grumman showed $2 billion in mystery money ("restricted programs", or secret stuff.) This means an unnamed "black project," and one of the likely ones is a prototype of the U.S. Air Force's next generation heavy bomber. The air force has been openly discussing building their next heavy bomber as pilotless, or as a "crew optional" aircraft. Meanwhile, over the past few years, considerable work has been done on smaller UAV bombers, that appear to be small scale versions of larger aircraft. The prime suspect is the X47B, a 15 ton, 36 feet long UAV, with a wingspan of 47 feet. It has a two ton payload and able to stay in the air for twelve hours. This is actually a navy project, a scaled up model of the X47A. The Department of Defense wants the air force and navy to agree on a single design, although the navy version will need stronger landing gear and better corrosion protection (from the salt water exposure) for carrier operations. Nevertheless, the X47B has "scale model prototype of UAV heavy bomber" written all over it. The $2 billion that Northrop Grumman had to show in its mandatory (as a corporation whose stock is publicly traded) financial reports would cover the costs for that.