I was working a few years back at British Airways and my job was working directly on Concorde flights. I got to fly it eleven times on test flights, to New York, Barbados and Eclipse of the Sun flight. I would still be there doing a job I loved, but when it got grounded I left BA. Yes, it did fly at 60,000 ft and you could see the curvature of the earth. The walls of the plane heated up in flight and the fuselage lengthened by enough to put a book into a space on the flight deck that was closed up on the ground. I spent a lot of time travelling up front - seems a long time ago now.