This thread is very interesting to me, as I would not even qualify as a spotter...just an enthusiast and a curious and interested flyer.
Thanks for the question Cherrylock, and thanks to all for the informative replies.
And to all you folk who take all those fantastic photos, keep 'em coming.
( especially B744's QANTAS style...one of my many weaknesses )
You are appreciated by many
Cheers, Scarbagjack