One thing puzzles me though. He says they are left by jets flying at heights of more than 8km - over 25,000 feet
The ones I usually see are from planes landing at or leaving Manchester airport, which is usually less than 20 miles west of where I am standing. So I would have thought the planes were lower than that
Funnily enough it was only the day before yesterday I was thinking that I must try to find someone who can teach me how to estimate the height of planes or clouds
One of my school geography teachers was very good at that, but in those days I found climatology/meteorology the least interesting part of the subject, so never paid much attention.
Oh if only I had known, when I was young
See also: Mystery con trails
