Economy
=====
Saver - M, B, U, K, Q, L, T, V, X, H
Flex - E, R, W
Flex Plus - Y

Business
=====
Saver - O, I
Flex - C
Flex Plus - J

First
===
Flex - A, P
Flex Plus - F

Others
====
Non Revenue Travel (airline employee, family and friends) - S
Discounted economy group fares - G
Economy Award (purchased with miles) - N
Business Award (purchased with miles, or upgraded with miles) - D
First Award (purchased with miles, or upgraded with miles) - Z