Coupla years ago I flew AMS-HKG in 10.35 mins in a Cathay 744, surfing the jet stream on 120+ miles tail wind over Russia for most of the trip. Acc the Capt. it was the 2nd fastest trip ever.... Arrived 1h30 mins ahead of schedule, which is no use because my party was still in his bed....
The flight info screen indicated speeds up to 1050 kms which is almost Mach1 I believe.
Cheers
cApT.kAoS