"What's that sound?"
"That? Oh, it's just the turbojets warming up - nothing to worry about."
"Oh right... and that whistling noise? Is that okay?"
"Sure - those are the ramjets kicking in."
"A ram-what? And what was that boom?!"
"That was the rocket motor. Remind me never to sit with you on hypersonic jet."
This is the sort of mild panic we imagine will engulf nervous flyers the world over should Airbus make good on a design they've just patented.
Titled ULTRA-RAPID AIR VEHICLE AND RELATED METHOD FOR AERIAL LOCOMOTION, the patent outlines a plane that would use "a system of motors formed by turbojets, ramjets and a rocket motor" to power a large aircraft to speeds of Mach 4.5 - over 3,000 miles per hour. Concorde only did Mach 2.
Following in the footsteps (wing spans?) of supersonic jets such as Concorde and Tupolev Tu-144, the Airbus design claims to have increased speed and performance, whilst also reducing the "bang" produced when breaking the sound barrier - which would help remove one of the antisocial issues that has plagued previous jets. Its average cruising speed could see a journey between London and New York take one hour.
The patent relates to the specific shape of the plane, including a "gothic delta wing", and a system of motors - powered in part by hydrogen "which is liquid or in a state of melted snow (slush)".
The plane would also cruise at an altitude 20km higher than most standard aircraft, nudging it toward the edge of Earth's atmosphere and avoiding air corridors that other planes navigate.
While it may be many years before a commercial airline uses such a jet, the patent does detail some military uses for the design, including "strategic reconnaissance, ultra-rapid transports of high added-value goods, and also equipped with elite commandos... As with satellites, the air vehicle of the invention offers almost total invulnerability to conventional antiaircraft systems". Should a rich, paranoid nation fancy funding Airbus' design, it could arrive a lot sooner.
Until then, we're just going to have to stick the conventional eight hour flight time between London and New York.
At least it means you can get a few films in, no?