I posted this (or something similar) about a month ago in this forum as I'd
tried to pano several for full effect and needed some advice. (never did do it).
Anyway, it lead to a few theories i'd never herad of. Hence the title.

http://forums.dpreview.com/forums/read.asp?forum=1019&message=13617477

Incidentally, they are just common or garden aircraft condensation trails.
iso 200 f/4.0 1/250th sec 22mm