UA's award seat inventory comes from a nonpublished inventory, called XF/XC/XY (and NY for 1K extra economy inventory). This is substantially different from almost any other carrier. If A (for F) and D (for C) inventory exists, the odds are greater that you can get an X seat.

UA upgrade inventory is NF and NC, again unpublished and again, greater odds if there is A/D inventory.

International fares must NOT be q/v/w to get an upgrade (except 1k systemwides) and Y/B counts as "full fare" for reduced mileage upgrades. Sometimes, on certain routings, the B fare isn't much higher than the cheapest, other times, its 4x as much.

[This message has been edited by Eastbay1K (edited 11-06-2000).]