The keyword is AMaRV. Developed late 1970s, early 80s, CNXed because it was the ultimate arms-control conversation-stopper.
Sounds like Boeing's trying to get aboard the Conventional Strike Missile (which is quietly forging ahead, not black but not publicised) and ease out LockMart's DARPA-rooted glide vehicle.
Boost glide vehicles are fun. There was the Culinary Institute of America's project back in the 1960s, called Isin... Hey, what's that black Omega doi