'Anywhere in the world in four hours': Jet breaks sound barrier in US

The return of supersonic travel has been surprisingly slow, but today, a significant milestone was reached as Boom Supersonic completed its first supersonic flight. The American company, building what it hopes will be the world’s fastest passenger jet, saw its test aircraft break the sound barrier for the first time in the Mojave Desert, California.

Boom’s XB-1 demonstrator aircraft’s supersonic flight marks the first time a privately developed jet has broken the sound barrier. Since its first flight in March 2024, the XB-1 has successfully completed 12 test flights, serving as a precursor to Boom’s Overture supersonic commercial airliner development.

In the recent flight, the XB-1 took off from the Mojave Air & Space Port, the same historic airspace where legendary pilot Chuck Yeager first broke the sound barrier in 1947. Piloted by Boom’s chief test pilot, Tristan “Geppetto” Brandenburg, the aircraft accelerated to Mach 1.1 (approximately 1,358 km/h), 10% faster than the speed of sound, which occurred about 12 minutes into the test flight at an altitude of approximately 35,000 feet (10,668 meters). Previously, the fastest speed the XB-1 had reached before its January 28th flight was Mach 0.95, just below the supersonic threshold of Mach 1, which it achieved in its last test flight on January 10th.

A live stream documented the historic moment for the first civilian supersonic jet built in the United States, as well as the world’s first independently developed supersonic jet. In the control room, 25 engineers reviewed real-time data during the mission. The highly anticipated aircraft has already received 130 orders and pre-orders from American Airlines, United Airlines, and Japan Airlines.

It has been nearly 55 years since the Concorde prototype 002 first flew at Mach 1 on March 25, 1970. And it has been more than 21 years since commercial supersonic travel ended with the last flight of the Anglo-French Concorde in November 2003. While the remaining Concordes gather dust in museums in the UK, US, and France, several contenders have emerged in the supersonic field, but so far, none have succeeded.

Boom Supersonic's ambitions remain high. CEO Blake Scholl told CNN last year that he expects supersonic aircraft to replace conventional airliners in our lifetimes. “I am a huge believer in the return of supersonic air travel and ultimately bringing it to every passenger on every route. But it’s not going to happen overnight,” he said in March 2024. Boom's plan is for the Overture to enter operation by the end of this decade, carrying 64 to 80 passengers at Mach 1.7, about twice the speed of today’s subsonic airliners.

Back in May 2021, when CNN Travel interviewed Scholl, he told us his dream was for people to one day be able to “fly anywhere in the world in four hours for $100 (AUD160).” In 2024, he confirmed this was still his “North Star.” The company plans for the Overture to one day operate on more than 600 routes worldwide. “Faster airplanes are more human-efficient, they’re more capital-efficient. You can do more flying with the same airplane and the same crew,” Scholl said. “By making the airplane faster, we can dramatically reduce all of the costs and impacts that go into an airplane. If we have faster airplanes, we don’t need as many airplanes.”

The XB-1 test aircraft has been used to validate new technologies being developed by Boom Supersonic. Like the Concorde, the XB-1 and Overture both have long noses and high angles of attack for takeoff and landing, which hinder pilot visibility of the runway. While the Concorde addressed this with a movable droop nose, Boom’s augmented reality vision system allows pilots to have excellent runway views without the added weight and complexity. “The advent of digital engineering is a huge enabler for the return of supersonic flight,” Scholl told CNN in 2024. “Aerodynamics, materials, propulsion: these are the three main areas where we have made huge advances over the Concorde.”

In the 1960s, the Concorde was developed in wind tunnels, which meant building expensive physical models, testing them, and then repeating. “When each iteration costs millions of dollars and takes months, you can’t test a lot of designs,” Scholl explained. But Boom has refined its aircraft's efficient aerodynamic design using computational fluid dynamics, which is “basically a digital wind tunnel. We can run the equivalent of hundreds of wind tunnel tests overnight in simulation, for a fraction of the cost of a real wind tunnel.” The XB-1 is constructed almost entirely from carbon fiber composite, a material chosen for its strength and light weight.

The Overture is designed to be powered by conventional jet engines and to use up to 100% sustainable aviation fuel (SAF). We’ve previously reported on CNN Travel about the slow rate of SAF adoption, and Scholl told CNN last year he’s aware of its current issues. “There’s not enough of it, and it’s too expensive, but it’s scaling up,” he said, but he believes it will one day be used for all long-haul air travel. He declared it is “the future of aviation.” Boom’s Overture Superfactory in Greensboro, North Carolina, was completed last year. It is designed to scale up to produce 66 Overture aircraft per year.