Originally Posted by rjque

While I'm sure VX does sometimes sell out their F cabins, my experience has been that there is usually at least one, if not multiple flights available for booking in F up to the 24-hour mark. The same is not true of at least one legacy carrier (CO). After the 24-hour mark, it becomes much more difficult to book or change flights, negating the benefit of a flexible ticket. It would be nice if VX wouldn't release all unsold inventory for upgrades so early.