Plane travel to the Antipodes from pretty much anywhere is a bit of a hike.
But experts say that is set to change as we enter an era of hypersonic passenger flight.
This new kind of jet could be the future of travel, and take people from London to Sydney in just four hours, reports LADbible.
UK company Reaction Engines is working on a new engine that would propel an aircraft which is around five times the speed of sound and more than twice the speed of Concorde.
That means it could reach a top speed of around 4,143mph, or Mach 5.4.
The engines could even be as operational as early as the 2030s, experts say.
Dr Graham Turnock of the UK Space Agency said "This is not sci-fi. This is not a pipe dream. This is literally in the works.
"It has the potential to turn air travel on its head. Certainly the way you conceive air travel will completely change in ten years' time."
However, the SABRE (Synergetic Air Breathing Rocket Engine) uses liquid gases like helium, which are able to cool incoming air from 1,000°C to -150°C in one hundredth of a second. This reduces the potential for melting, as such fast propulsion requires very high temperatures.
It remains to be seen if helium will still be accessible in 2030. Helium is a non-renewable resource. It is made on earth via nuclear decay of uranium, and it is recovered from mines.
Once it is released into the atmosphere it becomes uneconomical to recapture it, and eventually atmospheric helium will escape earth altogether because it is so light. This is an issue that many people outside the industries that use helium are unaware of, but one that will eventually affect them nonetheless.
The engine will also be powered by hydrogen, an "eco-friendly fuel" that produces water vapour when it burns.
Hydrogen has been touted as an environmentally friendly wonder fuel that can be used in vehicles and burns to produce only water as a by product. The problem with hydrogen is that producing it is far from environmentally friendly and storing it in a fuel tank is extremely dangerous. Researchers are turning to nanotechnology to overcome these problems.
The Reaction Engines website says: "SABRE engines are unique in delivering the fuel efficiency of a jet engine with the power and high speed ability of a rocket.
"Unlike jet engines, which are only capable of powering a vehicle up to Mach 3, three times the speed of sound, SABRE engines are capable of Mach 5.4 in air-breathing mode, and Mach 25 in rocket mode for space flight. They are simply going to revolutionise the way we travel around the globe, and into orbit.
Shaun Driscoll, of Reaction Engines, said this year at a UK Space Conference: "It's like a hybrid of a rocket engine and an aero engine, so it allows a rocket to breathe air... rockets really haven't progressed in 70 years, whereas aero engines have become very efficient.
"So, if you can combine an aero engine and a rocket you can have a very lightweight efficient propulsion system and basically create a space plane. The physics checks out but the challenge is building a test regime."