The only place you can fly supersonically is over the ocean, because of the noise. It's also more dangerous, and consumes vastly more fuel. The cost per passeng

The only place you can fly supersonically is over the ocean, because of the noise. It's also more dangerous, and consumes vastly more fuel. The cost per passenger is enormous, and the planes can't scale up large enough to offset it. The technology doesn't exist to make it economical. A big reason why supersonic flight isn't all that important is that the actual in-air flight time is usually under half the total trip time. If I'm flying from New York to London, the whole trip takes about twelve hours door-to-door. It takes more time to travel to the airport, wait around, board, taxi, land, taxi, go through immigration, retrieve luggage, and get to my destination than it does to fly across the Atlantic. Going Concorde-level supersonic would only reduce the whole trip time to about ten hours instead of twelve.