OK, in the spirit of the recently-concluded World Series, I'll dish up a hanging curveball:

I've done what I consider my best to divine the meaning of most of the acronyms used here on FT. One, however, still has me befuddled and that would be the acronym FO. It apparently has something to do with elite status on Delta. However, when I went to the DL web site and looked up their elite statuses, I could find no reference to FO or anything in long form that would contract to such an abbreviation.

So, please advise what FO stands for.

I've started the clock. It's ticking.....