Is This Concept Art Of A Mysterious Space Launch Mothership A Missing Link In Area 51's Past?

On January 14th, 2019 Boeing released a series of concept art images showing a very large, high-speed, high-altitude, mothership aircraft and its payload, a reusable air-launched space vehicle. The images are quite interesting for a number of reasons. First off, the setting seems to depict Groom Lake, aka Area 51. Second, they closely match a patent for just such a launch system that was filed by Boeing in 1986 and awarded in 1989. Finally, this concept is pretty much identical to a rumored program that supposedly flew from the base during the last decade of the 20th Century and possibly into the 21st Century. The timing of the patent and concept drawings also correlates with a number of factors that would support the existence of, or at least the logic behind procuring such an exotic space access system.