where did this phrase originate?

[pingping]

Fly by the seat of your pants

thanks!

[shaneystar2]

Some info here
http://www.phrases.org.uk/meanings/139400.html

[Catso]

I think it's far simpler than that. As you sit in the seat, you get to feel which direction/attitude you are flying in what you bum feels!

Which is fine providing you can also see the horizon as a confirmation. Sadly, those without instrument flying training relying solely on their 'pants' frequently come to a nasty, premature end as soon as they can't see which way is 'up'.

[pingping]

Thanks both - I had no idea where it had come from!