Originally Posted by Unitedloyalflyer

I'd say it is even more true today. Very few businesses pay for J (they view J as the old F). Plus, the more well do do leisure travelers are not wanting to sit in Y any longer, but may not want to spring for J.

Was a thread on the UA forum describing how they are overselling O, resulting in op ups into J. Too small O cabins are making J the new upgrade class (similar to F from before)