Originally Posted by
Air Houston
If you are buying full Y tickets 1-2 days before departure you should be able to upgrade instantly if there are any seats available in F and you have any kind of premiere status. I find on most flights that at least one F seat is not given away with the CPU hand outs and gets filled at the gate.
I certainly can't speak for "most" as sample size is small, but my personal experience includes trying to book on several flights out of IAH that have been completely full in F more than 24 hours from departure, including twice that I was actually trying to buy an F ticket. (In both those cases, I was able to reschedule my obligations and buy relatively inexpensive coach tickets instead, so this is CO's loss more than mine, I suppose.)