Elon Musk predicts rockets will one day be able to fly people from New York to Shanghai in just 39 minutes.
Musk's company, SpaceX, is developing a huge spacecraft to colonize Mars. It could also be used much closer to home.
Speaking at a space conference in Australia on Friday, Musk said the company had looked into applying the technology to whizzing people to different places on Earth in insanely fast times.
"The results are quite interesting," he said as a video showed a simulation of people boarding a rocket in New York that blasted off into space and then came back down to land in Shanghai.
Related: Elon Musk is aiming to land spaceships on Mars in 2022
"The great thing about going to space is there's no friction, so once you're out of the atmosphere ... it'll be smooth as silk, there's no weather," Musk said.
Most journeys between points on this planet will take less than 30 minutes, he predicted, and none should take longer than an hour.
In an Instagram post after the presentation, Musk said the cost per seat "should be about the same as full fare economy in an aircraft."
Musk teased the idea at the end of a presentation about SpaceX's plans to land cargo ships on Mars in 2022. Spaceships carrying people should follow by 2024.
The company is developing a giant reusable rocketship for those missions -- called BFR, or Big Falcon Rocket. Inside the company, it's nicknamed the "Big F--king Rocket." It plans to start building the first one by the middle of next year.
That's the same rocket that Musk says could be used to zoom people from city to city on Earth, traveling as fast as 27,000 kilometers per hour (17,000 mph).
Related: SpaceX to fly two space tourists around the moon in 2018
Unlike the Mars missions, Musk didn't offer any indication of when these super-fast journeys could become a reality.
He's not the only billionaire aiming to speed up travel.
Related: Branson! Musk! Bezos! The billionaire space race throwdown
Richard Branson has said he wants to perfect a "rocket plane" to transport people between cities on Earth via space. Branson, who's pursuing his space ambitions through Virgin Galactic, has forecast that the trip from New York to Sydney could one day take 30 minutes.
Musk also has plans to build an underground "hyperloop" network that can shuttle commuters between New York and Washington, which are about 230 miles apart, in 29 minutes.
-- Sherisse Pham contributed to this report.
