I saw this on reddit (the OP wrote it was from a ferry flight of a Gulfstream V) and was impressed.
It made me wonder: What is the maximum altitude that our real pilots achieved, why, and in which plane?
Source: https://www.reddit.com/r/aviation/comments/1ssnykp/fl510_first_time_for_me/
FL450 has been the max ceiling for both of the turbojets I’ve flown (PC-24 and Citations)… Didn’t go up there that frequently in the Citation but do it all the time in the PC-24. The Williams engines are medium bypass and go pretty good in the thin air.
I can’t believe the G-V uses Primus 1000 looking avionics. I thought it was a Lear 45..
17,999. I’ve yet to get clearance into Class A.
25000 ft as we don’t have drop down passenger 02 masks. A loaded Dash8 1-2-300 really struggles to climb any higher anyway.
Same as Beach, 450 in the Citation. The sky gets a really interesting dark blue/black up there!
Everything else, from Harriers to 737s were 410, or lower coughAirbuscough. 
As a pilot flying, FL470. As an observer during a pre-purchase test flight 50900ft. Both in the Global XRS. The airplane was not really happy at 50900ft which is why we didn’t push up to 510000 ft. So close, but no cigar. To be honest, there is no good reason to push up that high in a business jet other than bragging rights.
