Supersonic commercial passenger travel is almost certainly dead for the foreseeable future. (Small supersonic bizjets are another issue entirely.) Here's why:

Supersonic commercial passenger travel is almost certainly dead for the foreseeable future. (Small supersonic bizjets are another issue entirely.) Here's why: To start with, Concorde was a high-maintenance airframe, more like a military aircraft than an airliner. Each airliner averaged about a day of maintenance in the hangar per two hours of flight, so made one return trans-Atlantic crossing per week. It also burned roughly 100 tons of fuel shipping 100 passengers between NYC and London in 3h30m, compared to a 747 burning the same amount of fuel to ship 450 passengers between London and San Francisco; about 5-10x the fuel burn per passenger-mile. But the reason it eventually tanked in the market ... Suppose you're flying London-NYC, post-9/11. You can queue up for security checks 2 hours before you take your seat, then either fly on a regular subsonic airliner or Concorde. After your flight you spend 1 hour getting through immigration and customs at JFK. Total time on security/queueing: about 3 hours. Total time in flight: 3h30m or 7h. So Concorde only cuts your end-to-end travel time from 10h to 6h30m. Note that a Concorde seat is a cramped, narrow coach-class seat. Okay, there's first-class food and drink and a buffet in the departure lounge: but it's still coach-class leg-room. Meanwhile, a first class seat on a 747 gets you a lie-flat bed along with your posh nosh ... But if you have the money to fly Concorde, you have the money to pay for a seat on a private bizjet or a charter service like Netjets. It's still subsonic, but you by-pass the entire check-in/security/boarding/immigration/customs mess. Just drive through a gate and up to your bizjet, board it, and it takes off when you're ready for it, not vice versa. And on arrival, an immigration officer comes out to meet you and stamp your passport (if you pay extra -- part of the service). Travel time: 7h. The takeaway is that the super-rich/first class jet-set passengers deserted Concorde because they could get the same travel time for the same money on private business jets, without being treated like cattle by the TSA. Even if you could wave a magic wand and streamline the queueing/bureacracy for Concorde passengers, there remains the fact that if you re-started services tomorrow they'd only be able to manage one flight in each direction per day (if they had a fleet of six hulls magically preserved and ready to fly). Whereas the bizjet is ready to fly whenever the passenger wants it. Upshot: mass supersonic jet travel is dead for the time being. A market may exist for supersonic bizjets (and indeed Aerion claim to be bringing a Mach 1.5 bizjet to market within the next 5 years -- but someone or other has been saying some variation on this theme since about 1990). The only way we'll see supersonic passenger airliners the size of or larger than Concorde again is if we get a propulsion technology breakthrough that makes it feasible to run a scheduled daily-or-more-frequent service across distances that make it desirable -- LAX to Tokyo or Beijing, London to Sydney, and so on. Nuclear, anyone?