I flew it twice to JFK
rattled like hell on the ground as it is all loose for the joints to expand at 60k feet.
It went up at some angle, and then at 600ft you experienced what felt like a power loss as they had to pull back for noise purposes.
Then out to the edge of Irish waters and the announcement "We are just about to go supersonic and will accelerate to 1.8 the speed of sound and then we'll just 'drift' over the twice the speed."
And sure enough, it was like being in a high power automatic car, foot down hard and that thud in the small of the back. They had an speedometer in the cabin and the second time, a map/altimeter.
Space was tight, glorified economy seats, thickly padded.....service ok but better in BA 1st....the other highlight was seeing the curve on the Earth's surface, along with the rich azure blue of the sky. Look above and everything was inky black.
Then the descent into NY and you felt the speed coming down through the cards.....on the ground dedicated US customs and baggage, meaning you were out inside 10 mins with the choice of a Limo into NY or a chopper ride into the top of the PanAm building.