Skylon is a design for a spaceplane by the British company Reaction Engines Limited (REL).
It uses SABRE, a combined-cycle, air-breathing rocket engine, to reach orbit in a single stage. A fleet of vehicles is envisaged; the design is aiming for re-usability for more than 200 times.
As of 2012, only a small portion of the funding required to develop and build Skylon had been secured. The research and development work on the SABRE engine design is proceeding under a small European Space Agency (ESA) grant.