Supersonic-jet builder Aerion has revealed that Flexjet has called in an order of 20 Aerion AS2 supersonic jets, making the U.S.-based flight services provider the first company to make supersonic jet travel available since commercial supersonic travel ended in 2003.

Flexjet’s order is nothing to balk at; with each of Aerion’s AS2s fetching a $120-million price tag—that’s a total order of $2.4 billion if you’re keeping track. Each AS2 has a 30-foot-long cabin that will be specifically designed for Flexjet. The jet will carry eight to 12 passengers while traveling at speeds up to Mach 1.5 (990 mph).

Aerion’s supersonic jet has a range of 5,466 miles and with its speed can cut transatlantic travel times by up to three hours and slashes trans-Pacific travel by six or more hours. Flexjet pointed out that while three or even six hours doesn’t seem like a lot on paper, for constant international travelers the time savings really add up.

On a normal long-range business jet a traveler who logs 250,000 miles in a year would fly for around 500 hours, but that would only come out to 300 hours in an Aerion AS2.

Thanks to an ever-growing partnership with Airbus, Aerion has been able to expand and grow, making supersonic travel more of a reality to the business-jet market. The first AS2 flight is planned for 2021, with the first deliveries of the jets suggested to occur in 2023.