Originally Posted by StarG
That's my guess, too.
Guy Betsy, isn't it always (?) the case that the first letter of the fare basis is the class of service?
Like JOW, JRT, JOX, etc.
If it's a business class fare, then yes, that is how you'd look at it. The logical mind would say MKCSOR would mean
M: booking class.
K:Mid week
CSO: probably the promo name
R:Return
But as I've seen how CX fares go especially the special fares, the fare basis has almost nothing to do with the booking class. I've seen HLX6M fare basis' and the booking class is M. Or JOX1D and the booking class is D. This is more prevalent when it is not a straight off published fare but when it is a 'special' negotiated fare the agency has with CX.
Strange fare basis vs booking classes include:
Y2 : K
MPEX6 : L
YLEM : M
That is why I said I don't know.. the best is to check with Orbitz.