I have found these fascinating aeroballistic spaceplane concept images in an old Hungarian military book (Haditechnika 1973. Zrinyi Katonai Kiadó, Budapest, 1972.). The four pics show how the two-stage-to-orbit system with an airplane-like first stage would have worked (climbing, separation, rocket plane returning to Earth, spaceplane reaching orbit). Unfortunately there is no any piece of info in the book which company made these models.

The reusable launch vehicle and its crew returns to Earth:

The goal: some space station on Earth's orbit.

Blackstar?