http://acechick.typepad.com/knitchicks_features/knitting_on_planes/
Anyway the first Australian blog I visited said NO to knitting on planes so I read on and found a link to a wonderful source of sock yarn, Astrid's Dutch Obsessions in the Netherlands. I can't find this blog again but I like her idea that sock yarn doesn't count as stash so I ordered some too.
http://www.astridsdutchobsessions.com/scripts/default.asp
Astrid is very prompt with posting— I received the yarn in 7 days—and she doesn't charge an arm and a leg for posting.

Here it is: Trekking hand art 511 Trinidad 75% wool 25% polyamide and very soft. It came as a skein so this time we were very careful to wind the ball slowly.