Thank you so much for your help. I should have mentioned I will be using my United Mileage Plus for claiming the miles, so was particularly interesed how it will apply for United members. Actually I tried searching the Star Alliance forum, but there isn't a distinct answer about booking codes on RTW tickets, except a very old thread which said "B" class for most of the star alliance carriers on economy RTW. The document was excellent, so it would be good to post on Star Alliance forum also Thanks so much