I have travelled to and from Seattle with American Airlines. They and their One World partners fly all over the world. Miles are earned and can be used in all those companies.

In '97 we went from Sào Paulo to Seattle and a couple of weeks later, to Japan and Southeast Asia by Japan Airlines. In Southeast Asia we flew several airlines. All the miles of all the airlines were credited to our American Airlines account. They served for several trips to the States and one to Europe!

Regards. Susana São Paulo, Brasil