Ok I'm anything but an expert so here's my amature layman's comments... or more precisely an ordinary passenger's perspective on what I've heard so far about future aircraft.. So please don't shoot me if I get it all wrong LOL.. Whatever design it will be there must be commerical sense behind it or else it's doomed. Airbus & Boeing are showing us fancy cabins for the A380 & 7E7 with extra wide aisles, stores, gyms, lounges and whatnot.. looks good in the brochures and fancy graphics but most people here seem to think it will all be replaced by passenger seating as economic reality hits home and airlines try and pay for the plane.
Blended Wing Body aircraft have been put on the table as a future development. These concepts sure look cool and they may happen. God knows if they'll ever look like the concept vehicule. Some comments I've read here suggest they cannot be stretched, people want to be able to look outside and have natural light and the placement of the engines is top heavy etc.. so some work to be done on it techincally I suppose and some marketing to prepare passengers for a totally different type of flying vehicule if it ever materializes. I'm not sure if there are any great advantages over the current designs though.. other than seating large numbers of people in one plane.
You mentioned a single pilot or pilotless aircraft. I think that might be a possibility if America continues to focus on the airline industry in it's war against terror for any prolonged length of time. That is the USA though not the entire world and planes are supposed to be designed for many markets not just one. I'm not convinced the flying public is ready to get into a 400 seat widebody knowing only a computer is flying it. I think this would have to evolve out of a military concept aircraft first... so also a long way into the future for this one.
Hypersonic aircraft have also been thrown out as future possibilities. One I saw involved a jet like aircraft able to skip along the surface on the Earth's atmosphere firing it's engines only when it enters the atmosphere pushing it up and forward into open space and coming dawn for another "skip" into the next piece of atmosphere it finds itself in. The idea was to go from JFK
in about 2 hours. Passengers would be going in and out of gravity as the plane enters and leave the Earth's atmosphere to make the roughly 25 skips to Japan from New York. An interesting concept but quite far out there.. again maybe good for FedEx and the USAF
at least to start.
So unless someone pulls out a Concorde replacement in the near future I'm afraid airliners will more or less continue evolving as they have over the past 100 years. Perhaps getting bigger, more aerodynamic & fuel efficient, probably with more techinical wizardry for both the crew and passengers, hopefully more comfortable and hopefully more safe. I also hope the concept of the airport evolves with it so we don't find ourselves getting from A to B more efficiently and comfortably only to find we get bogged down in endless lines as we try to enter or leave the airport.. no doubt the whole evolution will be fascinating.