> It is. Just that it's the first such pair of aircraft that stay parked next to each other in all regimes, not just the one.

Apparently not! I learned from the video embedded in the article (just before the paragraph starting with "The Next Steps") that Scaled Composites has already built one: https://en.wikipedia.org/wiki/Scaled_Composites_White_Knight...

and from there I found a wikipedia category about them: https://en.wikipedia.org/wiki/Category:Twin-fuselage_aircraf... including another Burt Rutan design: https://en.wikipedia.org/wiki/Rutan_Boomerang

The Stratolaunch is just so much bigger.