| Proposed in the Air Force 2025 report. The B-3 is the designation for whatever bomber will replace aging B-52, B-1, and B-2 bombers in the United States Air Force. The B-52 is expected to be phased out within the next two decades, the B-1 within the next four, and the B-2 within the next five or six, which would leave the Air Force with no strategic bombers.
The reason the B-3 even exists is because nobody is researching large bomber aircraft anymore: the current vogue is UAV aircraft and the Joint Strike Fighter. The B-3 is pretty much there to kick strategic planners in the arse and tell them to design new bombers for that time around 2060 when the Air Force might be gone and the Chinese might rule the earth.
So far, there are very few designs for a potential B-3: the closest thing out there is the FB-22 modification of the F-22 Raptor fighter aircraft. | 
