Airbus has received a patent for a plane that could cross the Atlantic in an hour. It won’t be flying any time soon, though, and it would be far from luxurious.

The proposed plane has been described as hypersonic, though at 4.5 times the speed of sound that’s slightly below the most common interpretation of the term. It would still be double the speed of a Concorde.

Airbus details using three types of engine power. A standard jet engine would allow a traditional plane takeoff. Rocket boosters would then power a near-vertical takeoff to more than 100,000 feet, putting it well into the stratosphere. Here, missile-style ramjet engines would power the flight at the top speed before reversing the process for landing. The plane would use hydrogen fuel throughout.

As well as the speed benefits, the plane’s main advantage would be that the vertical climb would mean the sonic boom spread out rather than being directed to the ground and causing noise pollution. That would mean it could operate over land as well as across oceans making, for example, a three-hour Paris to Tokyo trip viable.

It wouldn’t be the most comfortable of journeys however: the unconventional flight path would mean passengers would have to sit in hammock-like seats to cope with the turbulence. The one-hour flight time across the Atlantic would only cover the period at full speed, so you’d have to add in take-off and landing to get the real journey time.

Airbus suggests that although commercial passengers would be the main audience, the plane could have military uses for rapid deployment of troops and equipment to far-flung locations.

Even if the technology does pan out, it’s questionable whether the plane would be financially viable, particularly as it would only be large enough to carry around 20 passengers. Airbus told The Guardian that ” These patents are often based on R&D concepts and ideas in a very nascent stage of conceptualization, and not every patent progresses to becoming a fully realized technology or product.”

In previous comments about the concept, the company said it could be 30 to 40 years before such a plane started operations.