See what’s fueling the return of supersonic passenger flights

In January, more than 100 people gathered at an airplane hangar in California to watch NASA unveil its X-59 demonstrator jet — a futuristic aircraft designed to travel faster than the speed of sound that has helped revive excitement for supersonic travel. There hasn’t been a commercial supersonic passenger jet since the Concorde stopped flying in 2003. Since then, supersonic jets — which travel faster than the speed of sound — have been used primarily by the military. But the space agency’s unveiling of the X-59, designed and built in partnership with Lockheed Martin, comes as a growing number of private companies are vying to bring back supersonic travel for the commercial market. Boom, Exosonic and Spike are among the companies promising modern supersonic travel that will be quieter, greener and more affordable than in the past. And at least one company — Hermeus — is exploring hypersonic flights, which would whisk passengers from New York to London in 90 minutes. But there are questions about whether these companies can make good on their claims given the economics of air travel and growing concerns about the impact of commercial aviation on the environment. Story lists five things to know about the effort to revive supersonic travel.<br/>