This is a known issue with co.com and their "superior" systems -- they are often confused by first and business class buckets, and the inventory comes and goes based on whether or not you're logged in.

I saw this on TG the other day -- C was available, but the minute I logged in, it was only F available.

I think it has something to do with Elite buckets that CO uses. CO uses the 3-cabin F bucket for some of its own Elites, and the logic is messed up when dealing with other carriers. I've had issues with pricing as well, where CO wants to charge 3-cabin F rates for 2-cabin F simply because they think that the code used for F is a 3-cabin code. Dumb it down to a non-Elite reservation, and it works fine.

Be sure the agent is feeding the segments in one by one. Sometimes they have trouble seeing or handling mixed-class itins (e.g., long-haul J connecting to a short Y hop). Also be sure the agent is looking for the right letter -- Business class is I, though CO uses I usually but O for Elites. You won't see O on other carriers internationally unless there is legitimate 3-cabin F.

If that doesn't work, see if UA agents can see the flights. If so, use the mileage transfer to book via UA. *net blocking aside, UA doesn't seem to have these sorts of glitches where their agents can't see stuff or it prices wrong.



Same is true of *net blocking allegations on UA. Many do not know how to prove *net blocking, and much that's blamed on *net blocking is not really *net blocking.