Originally Posted by tods27
I'm interested in the idea that an airline won't upgrade you (AA in OPs case and DP here) when a ticket has been endorsed over to them. Don't the collect a full Y fare from UA in this case? I'd think that they would be happy to let you use your DL or AA miles. I'm curious what UA does in a similar situation. For some reason I think that I did this years ago on US with a ticket endorsed over from UA, but can't really remember.
As explained to me, UA was not endorsing my whole ticket over to AA, simply the BOS-LHR segment. The remainder of the itinerary remained on UA. So AAdvantage refused to let me upgrade, since the "whole ticket" was not sent to AA.
I did get AA miles for the trip, and in fact that put me over the level for the AA Platinum ( = UA 1P) challenge, so I now have status on AA
. I'm doing BOS-SFO again tomorrow on AA, first time with status. (But don't worry UA, I have 4 more transcons and/or transponds booked and paid for with you.)