Originally Posted by
smiles33
....I see an option on the United website to pay cash for J seats and an option to use mileage + cash for the waiting list, but no option to just upgrade outright with miles. Perhaps that means they already sold out of mileage + cash to upgrade?....
Uograde co-pays vary with fare clad purchased. You can buy several fare classes with no co-pay, but the ticket price will probably negate the co-pay savings. United does not “sell out” of upgrade space. The R space required is not necessarily populated when the flight is first booksble. It might be, it might be later, or mileage upgrades may never be available. This thread should eventually be merged with an existing thread where the wiki may help you.