So, I'm desperately trying to finagle my way back to Spain this summer and, so far at least, have been stymied by $400 - $600 plane tickets. I've heard that air courier flights present an affordable option for the cheap (like me ) but know absolutly NOTHING about this. So -- while this post may be a little random -- if anyone's ever done this or knows anything about it...pipe up PLEASE !

Never done it, don't know anyone who has, but this being gunks.com doesn't prevent pasting up something from Google as knowledgeable fact!

See: http://www.guidebookwriters.com/authors/andrewdean/faq56.htm

One of the more interesting factoids from that page:
Air couriers relinquish the luxury of planning too far ahead and checking personal luggage in exchange for (often steeply) discounted airline tickets. The courier's baggage allowance is used by the courier company to ship time-sensitive packages and documents.

A reoccuring theme of my air courier research is neatly summed up in a quote from the previous link:
"The best, if time consuming, way to get hooked up with an air courier flight is to do your research independently by phone (and in person wherever possible)."
Which would be helpful -- that is, if there were further details about *how* to do this "independent research."