OK, thanks for the info. I now see that I would buy the Zed tix through UA just like an ID90.

I did a bit of sleuthing to try and pin down the zed loads. I found a website (www.seatcounter.com) that supposedly lists seat availability by booking class. It shows booking classes A through Z, #s 0-9. I compared this info for a 9/25 LAX-SYD flight on UA's employee site, and it seems that the higher the # the more seats are available. The booking class stumps me, though. I thought that there was only 3? Flyzed shows a green smiley face which agrees with UA's #s. Flyzed also displays a red face for QF and AA flights that same day, which agrees with the low red numbers on seatcounter.

So, has anyone used this seatcounter.com and know exactly what the As-Zs mean? I thought that FBE meant first, business, economy?

Any help is appreciated. I'm trying to plan a far away trip later next month and I'd prefer not to be stranded. Not that it wouldn't be so bad!