I am not particularly convinced of the physics of hypersonic flight.
BA was due to fly LHR-SYD in 14 hours - with 2 fuel stops (Bahrain and Singapore). BA, and SQ, DID fly LHR-SIN in 9 hours with the fuel stop in Bahrain.
How was it, to spend 9 hours in a plane designed for midgets, preferrably midgets without any hand luggage? Where economy class tourists had twice the room on a 747 for a tenth of the price?