Originally Posted by
sbm12
I should clarify that this is for reward bookings. For paid RTW I believe that CO books the Business ticket in to the Z bucket, based on - among other things - the KE rules that were posted earlier and that I'm re-posting
here.
Also, on all three US carriers you're stuck in Y for domestic US flights on a J ticket. I'm pretty sure that NW offers a buy-up on a segment-by-segment basis, but CO/DL do not.
I did a RTW reward in Biz, and I certainly booked a CO EZE-IAH flight, which I'm 98% sure is a BF flight. Every domestic flight was a FC flight as well.