Implying they have a pretty dumb system of deciding whether a contrail is generated, seemingly comparing altitude difference.
I wonder if it disappears as you go higher, then reappears as you descend, matching the OP observation in reverse.
Implying they have a pretty dumb system of deciding whether a contrail is generated, seemingly comparing altitude difference.
I wonder if it disappears as you go higher, then reappears as you descend, matching the OP observation in reverse.