Intriguing announcement.
https://www.boeing.com/features/2018...t-vehicle.page
For Boeing to even float this as an idea would suggest that even absent the SR-72 supposed sightings etc. the military classified technology is a lot more advanced than we're currently aware of.
Flight International thinks they're just flying a very speculative kite - so to speak.
https://www.flightglobal.com/news/ar...c-airl-449749/
The concept follows a long tradition of aircraft companies releasing highly ambitious, long-term design concepts meant to inspire the public and attract young engineers seeking the most challenging assignments.