On LH Group and SK, I bid for upgrades well in advance of the flight. I've had enough experience by now to figure out what bids are accepted and what are not. I was offered a cash UG on all but one of my KL flights over the past 2 years at OLCI. On BA, AF and TK, I have had > 50% success at airport check in by asking if there were any J seats available for purchase. In every case, the J upgrades for TATL flights have ranged from $600-900 USD.

While I have lifetime Gold on UA/*A, I have no status on any ST or OW airline. You have to be persistent. On my last BA TATL, I was told there were J seats available but they weren't releasing them. I went to the BA lounge, and pointed out to the BA CSR that they could make $$ by letting me buy up to Club World and giving my Y seat to an oversold pax. She called someone and then said to me "come see me at the gate when it opens." I got the J seat.