[aaron38]

^^^ The Chicago-Asia flights that used to be 747s are all 777s now. Still a very big comfortable plane, twin isles. It's just that the 777 is a much more efficient airframe.

For the form factor, it's just that we're constrained by physics. Airliners are very conservative vehicles. They are passively stable. They can glide without power. They are simple and strong.

Yes there are innovative solutions to the aerodynamic problems. But they weigh more per passenger, and/or they are dynamically stable. Meaning they drop like a rock if the computer crashes. Personally I think that's what's holding back the flying wing designs, which is the option most likely to replace the 707 form. But no one wants to roll the dice.