I belong to the United Airlines frequent flyer program. It's a member of the "Star Alliance". The Star Alliance consists of a number of airlines, including Thai Air. Well, you're supposed to be able to earn United miles flying on Star Alliance carriers. So, when I travelled to Thailand last time, I flew out of New York on the non-stop Thai flight because it's a LOT quicker. (United stops at Chicago, and Narita enroute to BKK). Anyway, I gave them my United number. To my dismay, I find that I only get 50% mileage allowance because I didn't fly with an expensive enough ticket. It took me some time to find it, but here's a Thai air website that explains it a bit:
http://www.thaiair.com/Royal_Orchid_Plu ... rlines.htm
A word to the wise if you're trying to accumulate mileage for a free ticket.