I admit that I have not studied the fare classes in order learn when upgrades are available. The only thing I do know is that there is a relationship between R fares and upgrade availability. Please forgive my willful ignorance, but it is only now becoming increasingly important to me, as I'm now choosing to buy so many front cabin tickets if I know that there's no way I'll be upgraded. My Wednesday, 6/27 afternoon flight from LGA to IAH shows ten of sixteen First Class seats open. I am Platinum, my fare class is L, and we are within the 72 hour window, with equally high seat availability showing in the E+ seat map. The economy seat map is sold out with the exception of two last row seats. The Fare Classes showing on the link are: F8, JN8, A8, Z4, ZN4, P4, PN8, Y9, YN9, B9, M9, E9, U9, H9, HN9, Q9, V9, W9, S9, T6, L4, K1, G0, N0 Seeing no R or RN classes on this list, does that mean that there will be no upgrades until the 30 minute window is reached? I was also looking at some BOG to BCN tickets for January. The EWR-BCN portions were all showing R0 and RN0, even though there have only been a handful of total seats sold on those flights. If we go, it will be with the plan of using GPUs. I don't even want to go if we can't use them, as those are some long flights. Are the R fares the same for international flights as they are for domestic, or do they use a different fare class to indicate their upgrade availability? Thanks in advance for the accurate info I have come to rely upon here.