By the way, Concorde operated above FL450... well above...
and the military have nothing that high?? I'll wager that, at times, they have traffic higher. I've certainly assisted a controller working a track at FL500 in the descent! (took bloody ages too... coffee went cold!)
At the end of the day it gets dark... we all get paid... and we all
share the airspace :-)
One BIG happy family
