I wonder how this will impact air travel. It is a real shame that after Concord retired there is no supersonic jetliner in service, which at least kept the dream alive even if Concord is expensive and short legged. I believe no viable program exists right now for supersonic jetliners. The problem, if I recall correctly from my aerospace professor, is not the jet engine's thrust but heat generated from friction with air. If this Sabre engine can get the airplane mostly out of atmosphere cheaply, heat problem can be alleviated. I don't know how practical my guess is, but if it works, the market potential is immense.