Future SST
Is there any development along the lines of a supersonic business jet?
I'd think that the market for air travel breaks down into the masses, willing to pile on board a huge cattle car type AC and sit there for a few hours longer just to save a few dollars (Pounds, Euros, etc.). And then there's a smaller market segment willing to pay whatever for first class accommodations. And possibly to shave a few hours off a transatlantic or transpacific flight.
You are going to want to schedule a few flights on each route per day. When the rich folks (or business people) want to fly, they want to fly NOW. So the passenger loads will be spread across a number of flights, reducing the per aircraft capacity requirements.