In article ,
(Sylvain) writes:

flying across to Europe from California once in a while, my take is that
I don't think getting faster aircraft is going to make much of a difference:
a significantly higher amount of time (and disconfort) could be saved by
improving the airports and routings.

This reality is what doomed the "sonic cruiser" which would have been less than
15% faster than conventional airliners. Under the hub & spoke concept of air
travel these days, there are relatively few trip where a passenger spends more
time in the airplane than they spend in, or getting to-from terminals.

John