First Class
F = Full-Fare First Class
P = First Class
A = First Class Discounted
R = First Class Suites
Business Class
C, J = Full-fare Business Class,
D, I, Z = Business Class Discounted,
Economy Class
Full fare: Y, B
Standard fare: M, H, N
Special or discount fares: G, K, L, O, Q, S, T, U, V, W, X
or for airlines with Premium Economy
S = Economy/Coach; On some airlines it can also stand for 'Super Comfort' (Premium Economy)
T = Economy/Coach Discounted, or Premium
W = Economy/Coach Discounted, or Premium, or award