Originally Posted by
ft101
My latest information (but could well be out of date)
R, Y - Economy Flex Plus
K, U, B, M - Ecconomy Flex
T, L, Q, N - Economy Saver
X, V - Economy Special
J, C - Business Flex Plus
I - Business Flex
O - Business Saver
H - Business Special
Premium Economy seems to be W and E. Flex Plus and ?
It's the first letter in the fare code on your e-ticket.
To add:
F - First flex plus
A- First flex. A used to have 2 ‘levels’, Flex and Saver. First saver does not seem to exist anymore.