There are two startup passenger jet manufacturers building factories at the Piedmont Triad Airport in Greensboro, NC. One is Boom SuperSonic, the other JetZero. Of the two, I think JetZero is most likely to succeed. If they can actually deliver 50% less fuel burn than the current offerings from Airbus and Boeing they will have airlines clamoring for their aircraft. Even if Boom gets their plane in the air (itself a big question mark since all the engine suppliers told them they could not build an engine to their requirements so they decided to also build the engine themselves), it’s not clear to me that there’s a more viable market today for supersonic air travel than there was when the Concorde was flying. Plenty of people would like to fly that fast, but I don’t think there are plenty who can afford it.