In order to book an upgradable fare on United you have to buy a ticket in fare class W or higher. Here are the fare classes above W.
V
Q
H
U
E
M
B
Y
Only airlines could convolute something so simple as the ordering of the alphabet.
Related
for those of you waiting for 3DTV without glasses, here
Great Infograph on Frequent Flyer Traveling from the New York
I’ve fallen drastically behind in keeping my travel log up-to-date.