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
Lost cities. Whispered legends. Dense green canopies that hide entire
Introduction SLS Hotel at Beverly Hills Cooks County As I
Through the first three quarters of iPad availability, Apple sold