Originally Posted by
jarino
For both UA and LH, RTW coach is in M, not in H or B as quoted in #1
S is used for NEGO fares, too, like L'tur last minute sometimes.
I think P is not used as LH banned all non-rev F travel. When R, N, O, I, X showed up in SABRE for some time, P and J were the only unused letters.