By Sputnik, Matr5153, and Chupacabra.
British Aerospace proposed airbreathing launcher from the mid-1980's. Trolley-launched. Also includes Interim HOTOL, a pure-rocket 1990 proposal (requires Kev33's An-225, not included). CVEL-compatible.
Re-compile for Orbiter 2010. Kev33's An-225 also required a re-compile to allow the Interim HOTOL launch. Install the An-225 FIRST; HOTOL will overwrite K-An-225.dll.