There are a few aviation brands looking to bring back supersonic passenger flights since the Concorde fleet retired. But Colorado’s Boom Technology has emerged as the main contender.

Boom has completed its first round of wind-tunnel testing on its supersonic prototype, which is a critical step in developing a full-scale example.

The scaled-down model was flown inside a wind tunnel at Wichita State University in Kansas, with the results confirming Boom’s expectations and calculations for low-speed aerodynamics, control, and stability.

Boom’s next step is assembling its XB-1 Demonstrator, which is a technologically paired one-third-scale version of what the Denver-based aerospace brand’s production craft. The first XB-1 flights are expected to come later this year.

Boom claims it will offer air travel at Mach 2.2, faster than the Mach 2.0 that the Concorde fleet achieved, and 2.6 times faster than the Mach 0.85 of regular airliner travel.

The eventual Boom production plane will offer seating for 45 passengers and is expected to make the trip from New York to London in just three hours and 15 minutes. Tentative fares are currently estimated to run $2,500 one-way.

The company is looking to begin passenger flights in 2023.