I had not heard of this specific proposal before, but the Skylon is a type of proposed aerospatial craft which is featured so prominently in the opening chapter of LOST ON THE LAST CONTINENT:
Skylon is a series of designs for a single-stage-to-orbit spaceplane using SABRE, a combined-cycle, air-breathing rocket propulsion system. The vehicle design is for a hydrogen-fuelled aircraft that would take off from a purpose-built runway, and accelerate to Mach 5.4 at an 85,000 ft altitude (compared to typical airliners’ 30,000 ft) using the atmosphere’s oxygen before switching the engines to use the internal liquid oxygen (LOX) supply to take her into orbit.
The design is currently being developed, among other places by British company Reaction Engines Limited.
For the record, here is the description of aerospace plane from my adventure novel:
The magnificent machine was dubbed the Shooting Star VII. … The black hull was bat-shaped, streamlined to the ultimate degree. She had no tailfin, no large surfaces to reflect radar. She was, in fact, an aerospace plane. No ordinary jet, she was driven by a combination of turbo-ramjets and liquid-fuel rockets. She could achieve supersonic speeds and low earth orbit.
