Originally Posted by
jobevers
I'm a bit new to this; I thought in order for you to be able to get miles for a different airline the two airlines had to have a codeshare agreement.... but thanks for clearing that up.
Nope, codesharing just means that one airline sells seat on another airline's aircraft. Sort of like UA doing business as Air India (AI sells the tickets and puts its code on the ticket, but the a/c is United). But frequent flyer agreements just allow you to earn miles on the others. For that though, if you're in Y make sure that the fare class you bought in economy is eligible.