Originally Posted by
Swanhunter
You might get an offer via OLCI but IME if the flight is that full they may only sell at physical check in or quite possibly not at all.
Didn't I read in another thread that when flights are full and upgrade options are made available that they tend to be at an unattractive price?
I wouldn't know personally as I have only ever flown as booked, been upgraded, or volunteered for another flight with some compensation, never upgraded for cash at OLCI or at the airport.