NASA's supersonic jet recently hit a testing milestone as the agency looks to set the stage for commercial air travel that whizzes passengers to their destinations faster than the speed of sound.
In June, the X-59 experimental aircraft hit supersonic speeds for the first time since testing began in fall 2025. Last month, the U.S. space agency conducted the airplane’s 25th test mission.
The landmark flight test comes as NASA not only aims to help restore supersonic flights in the U.S., but to revolutionize the mode of travel by reducing the amount of noise involved. Built by aerospace contractor Lockheed Martin, X-59 is designed to not only break the sound barrier by surpassing Mach-1 speeds, but to do it without generating sonic booms that sound like
cracks of thunder to observers on the ground.
Here's the latest on testing of the X-59 supersonic jet, which could soon be flying over a city near you.
NASA's supersonic jet completes 25th flight test
Following its maiden flight on Oct. 28, 2025, NASA's experimental supersonic jet reached its 25th flight test Aug. 21.
After a test pilot taxied the aircraft from a hangar at NASA’s Armstrong Flight Research Center, the X-59 jet took off and landed at Edwards Air Force Base in California. During the 72-minute flight, the jet reached a top speed of more than 920 mph while climbing to an altitude of 49,000 feet, NASA said in a Sept. 4 press release.
The X-59 jet was accompanied by a NASA F‑15 aircraft known as a "chase plane" that kept an eye on the research plane.
The milestone flight came more than two months after the X-59 reached supersonic speeds for the first time in June, flying faster than the speed of sound.
What is NASA's X-59 supersonic airplane?
The X-59 supersonic jet is the centerpiece of NASA's Quesst mission, which seeks to reduce air travel time in the U.S. and the world by making commercial supersonic flights over land possible.
Supersonic speeds are ubiquitous for spaceflight, as spacecraft have to surpass the speed of sound in order to reach orbit after a rocket launch. However, commercial passenger jets typically travel below 600 mph, which is not fast enough to break the sound barrier and become supersonic.
The X-59 is a research aircraft meant only to gather data that could inform future commercial supersonic flight.
Why does NASA want to test supersonic commercial flights?
While supersonic air travel is nothing new, it has been more than two decades since an international commercial supersonic flight program has existed. And in the U.S., the unwelcome noise of supersonic flights among the general public have led them to be banned since 1973.
Now, private entrepreneurs and President Donald Trump's administration are renewing a push for supersonic flights in the United States.
What makes the technology that the X-59 jet is testing different is that it's designed to make future flights not only incredibly fast, but remarkably quiet – a key factor that NASA officials say could help ease the half-century U.S. ban.
The aircraft was developed to fly quietly at supersonic speeds without generating sonic booms – the brief, thunder-like noises that occur when anything surpasses the speed of sound. Instead of producing a jarring sonic boom, the aircraft is designed to create what NASA officials call "a quiet thump" that will be less disruptive to people on the ground as a future airliner soars overhead.
What's next for X-59? NASA wants to fly jet over US cities
So far, NASA has been conducting test flights of the X-59 under the first phase of missions that has sought to gradually increase the speed and altitude at which the airplane flies. Eventually, NASA wants the X-59 to reach its maximum speed and altitude of of 1,218 mph and 60,000 feet high.
Because the chase plane that accompanies the X-59 causes sonic booms of its own, any noise the X-59 has made (or not made) has so far been masked.
NASA, though, plans for the second phase of testing to focus on using ground and air-based tools to verify that the supersonic jet is cruising as quietly as intended by dispersing the shock waves that typically merge into a sonic boom.
Future tests will involve flying the airplane over populated U.S. cities to see how people on the ground react to the plane as it speeds by at more than 1,000 mph and 55,000 feet high. Data gathered from those tests will be shared with U.S. and international regulators, NASA said.
Eric Lagatta is the Space Connect reporter for the USA TODAY Network. Reach him at elagatta@usatodayco.com
This article originally appeared on USA TODAY: NASA's quiet supersonic jet 1 step closer to flying over US cities
