Spike Aerospace S-512
The S-512 will travel at Mach 1.8 and carry up to 18 people. Spike Aerospace

A crew of ambitious aeronautical engineers claims it can build a supersonic business jet that will fly from Tokyo to Los Angeles in just eight hours. But there is one catch: It will cost a prospective buyer about $80 million.

The Boston-based Spike Crew is about to embark on the construction of the Spike Aerospace S-512, which will fly at speeds of up to Mach 1.8 (1,370 mph) and be able to carry about 18 passengers.

The team is made up of former Airbus (BMAD:EAD), Bombardier Inc. (TO:BBDb) and Gulfstream (NYSE:GD) engineers, with a sprinkling of entrepreneurs and investors. But they're not the first to promise a supersonic private jet. In 2009, Aerion promised a 12-seat jet that would be ready for take-off in 2015 and cost exactly $80 million, but that estimate has been pushed back to 2021. Spike claims its plane will be available in December 2018.

Whichever jet is ready first, it will meet with some strict FAA legislation that bans supersonic travel across the continental U.S., with just a few exceptions. So for now, Spike and Aerion are limited to flying across oceans. Major airline manufacturers, and even NASA, have been working on a way to have aircraft travel at supersonic speeds without causing a sonic boom.

The big price tag and travel limitations mean that Gulfstream’s 550 jet and The Boeing Company's (NYSE:BA) Business Jet, coming in at $59.9 million and $55.5 million, respectively, don’t have much to worry about just yet.