I can book a transatlantic trip on Luftansa.com that is operated by UAL. The fare code on the website is K which is not upgradable as a LU flight. However, if it was a UAL K class fare it could be upgraded with 80 plus points. I don't want to book it if I can't have the chance to use P. I called United MP and they said it would not be upgradable but I read elsewhere on this forum that the fare basis of the marketing carrier isn't the same as the operating carrier but it's the equivalent fare basis. My question is: Will there be a separate fare class for UAL as the operating airline or is the fare basis going to be LU's K class. It's a basic economy on LU but allows for 1 checked bag. I am thoroughly confused. I need expert help. Thanks.