To the dismay of weary business travelers the world over, the idea of being able to get from one point on Earth to an entirely different point within four hours seems like either science fiction or the result of a particularly unambitious travel itinerary. But that may be about to change, with a British company announcing that it has successfully completed tests for a new rocket propulsion system that significantly changes consumer air travel – or, at least, the amount of time a consumer spends in the air – forever.

Reaction Engines has created a new type of jet engine that “breathes” air, something that allows the aircraft to move at speeds that Reaction claims are five times the speed of sound. Developed over a 20-year period, Reaction’s SABRE – which stands for Synergetic Air-Breathing Rocket Engine – can operate in two modes: “air-breathing” and “rocket,” a dual system that is being described as a “major breakthrough in propulsion worldwide.”

The breakthrough comes from the addition of this “air-breathing” mode to an orbit propulsion system for the first time, which allows vehicles using SABRE power to significantly lighten their load in terms of the on-board oxidant (such as liquid oxygen) necessary to keep conventional rocket engines going. Instead, SABRE’s air-breathing mode allows the vehicles to, in the words of Reaction, “[suck] in atmospheric air as a source of oxygen (as in a typical jet engine) to burn with its liquid hydrogen fuel in the rocket combustion chamber” before the engine switches to rocket mode above the atmosphere. This transformation, according to Reaction, “removes the necessity for massive throw-away first stages that are jettisoned once the oxidant they contain has been used up, allowing the development of the first fully re-usable space access vehicles such as Skylon.”

The European Space Agency has finished evaluating SABRE’s capabilities, and reported back that everything seems to be working out just fine. British Minister for Universities and Science, David Willetts, released a statement after the ESA’s thumbs-up, calling the SABRE “a remarkable achievement for a remarkable company” that demonstrated that “Britain remains at the forefront of technological innovation and can get ahead in the global race. This technology could revolutionize the future of air and space travel.”

Alan Bond, Reaction’s founder, said that the ESA’s testing “represent a fundamental breakthrough in propulsion technology” that will “force a radical re-think of the design of the underlying thermodynamic cycles of aerospace engines” and “open up completely different operational characteristics such as high Mach cruise and low-cost, re-useable space access.”

Further testing awaits, of course, but the question now exists: Which airline will be daring enough to offer the first hypersonic flights across the Atlantic (and beyond)?