The US is taking steps to reverse an over five-decade ban on trans-continental supersonic flights as it unveiled a proposed rule that sets noise-based standards for operating such aircraft.
The US Department of Transportation move on Tuesday came after NASA successfully tested the experimental X-59 aircraft that flew faster than the speed of sound without producing the loud sonic booms usually associated with such flights.
Sonic booms can rattle windows and, at their most severe, risk damaging buildings.
The proposed FAA rule intends to replace the 1973 ban on overland supersonic flight with a noise limit.
The proposed rule allows aircraft to fly faster than Mach 1 (the speed of sound, 767 miles per hour) over land as long as the resulting noise stays below a set level.
The FAA also plans to propose another rule later this year, establishing landing and takeoff noise standards for supersonic aircraft. The two rules are expected to be finalised by mid-2027.
Currently, airline operators require special flight authorisation from the Federal Aviation Administration (FAA) to fly aircraft faster than Mach 1, only for research and testing purposes over isolated areas.
"Advances in aerospace engineering, materials science, noise reduction, and new operational concepts will eliminate the old sonic boom," Federal Aviation Administration (FAA) chief Bryan Bedford said in a statement.
"This means we can ultimately repeal the ban from the 1970s on supersonic flight over US territory while minimising noise impacts to residents in communities along the route and near airports," Bedford said.
Earlier this month, NASA demonstrated its "quiet" supersonic flight when it tested the X-59 aircraft that reached a top speed of 713 miles per hour (Mach 1.1) at an altitude of 43,400 feet.
The X-59 is designed to fly at supersonic speeds while creating only a quiet thump instead of a loud sonic boom, NASA said in a statement on June 5.
"Restoring supersonic flight over land isn't just about speed, it's about unleashing American innovation and ushering in a Golden Age of Travel," said US Transportation Secretary Sean P Duffy.
"Thanks to President Trump's leadership, we are working at lightning speed to safely enable the next quantum leap in aviation technology and deliver an exciting new way to fly to the American flying public," Duffy said.
"For too long, outdated rules held back our engineers and manufacturers. Under President Trump's leadership, we are clearing the runway for supersonic flight, strengthening our industrial base, creating high-skilled jobs, and ensuring the future of aviation is invented and built in America," Director of the White House Office of Science and Technology Policy Michael Kratsios said in a statement.
American ingenuity broke the sound barrier once before, and today's action ensures it will define the new Golden Age of Aviation."
Air France and British Airways introduced Concorde, which flew at twice the speed of sound (Mach 2) and crossed the Atlantic Ocean in about 3.5 hours.
However, such speed was allowed only above the ocean and the flight and the plane had to operate at subsonic speed over land. The Concorde service was discontinued in 2003 due to high operating costs.
Besides NASA, other US companies working on supersonic aircraft include Boom Supersonic and Spike Aerospace who also plan to offer future transatlantic flights in under four hours.