From New York City to London in just 90 minutes? NASA is exploring the potential of a supersonic jet that one day could do just that.

Transatlantic jetliners currently travel at about 600 mph, according to the federal space agency. But NASA's concept for a plane could theoretically travel at Mach 4 -- four times faster than the Mach 1, the speed of sound, which is typically 761 mph at sea level.

The plane's unique shape also would theoretically allow supersonic shockwaves to be spread out, preventing the familiar sonic boom from occurring on the ground when the aircraft breaks the sound barrier.

If the concept gets off the ground, it would be the first time in more than two decades that there has been a supersonic transatlantic flight since the Concorde, jointly developed by the British and French over 60 years ago, was retired in 2003 due to operating costs.

The news comes as NASA's separate Quesst mission involving its X-59 plane gets underway, one of the goals of which is amending the rules that prohibit commercial supersonic flight over land, in hopes of dramatically reducing travel times in the U.S. and overseas, a NASA spokesperson told ABC News.

Starting in 2025, the Quesst mission will see the X-59 fly over some U.S. cities and ask residents to share how they respond to the sound, NASA said. The agency will analyze the data and submit it to U.S. and international regulators in 2027 to consider allowing new commercial supersonic flights, including passenger flights.

NASA said it has been conducting studies on about 50 commercial routes to gather data on how humans respond to the sound generated during supersonic flights. Because the federal government banned all civilian supersonic flights over land 50 years ago, the studies examined transoceanic travel.

Lori Ozoroski, project manager for NASA's Commercial Supersonic Technology Project, said similar studies were conducted more than a decade ago, looking at flights traveling between Mach 1.6 and 1.8, just over half again as fast as the speed of sound.

"Those resulting roadmaps helped guide NASA research efforts since, including those leading to the X-59," Ozoroski said in a statement to ABC News. "These new studies will both refresh those looks at technology roadmaps and identify additional research needs for a broader high-speed range."

The new studies, led by NASA's Advanced Air Vehicles Program, involve two teams made up of several companies that will "develop concept designs and technology roadmaps" to outline any risks or challenges of flying planes at speeds of Mach 2 or greater.

According to NASA, Boeing is leading the first team, while the second is being led by Northrop Grumman Aeronautics Systems, which produces aircraft and spacecraft as well as defense technology. The NASA spokesperson said the teams will be looking at gaps in technology as well as early concept designs, but notes there is no technology or aircraft to these ends currently in development.

"The design concepts and technology roadmaps are really important to have in our hands when the companies are finished," Mary Jo Long-Davis, manager of NASA's Hypersonic Technology Project, said in a statement to ABC News. "We are also collectively conscious of the need to account for safety, efficiency, economic, and societal considerations."

"It's important to innovate responsibly so we return benefits to travelers and do no harm to the environment," Long-Davis said.