Last month, Airbus engineers quietly received a patent for a new — and ambitious — type of a plane: a hypersonic, "ultra-rapid" jet capable of traveling at up to about 4.5 times the speed of sound, and fast enough to get from Paris to San Francisco in about three hours.

The patent, spotted by YouTuber PatentYogi, name-checks two supersonic crafts — the Tupolev Tu-144 and Concorde — but claims the Airbus design "enables the performance of both these aircraft to be improved very considerably." The patent also claims the craft would be able to significantly reduce the "bang" of the sound barrier, possibly carrying about 20 passengers on board.

The plane, according to the patent, would work with a few different propulsion systems. First, turbojets and a rocket motor would propel the plane to a "near-vertical" position in the air, before the plane would turn toward its destination, sent forward by powerful wing-mounted ramjets that would power it to top speed.