I was trying to use miles for a front cabin trip CLE to CDG. There was a lot of availability on Continental for the outbound, but only a Northwest flight for the return. I decided to go for it, but as I progressed, Co.com revealed that the CLE/EWR leg was a G class, and the Northwest return was a D class from Paris to Detroit, and an A from Detroit to Cleveland, with no explanation of what these classes are. Northwest's web site was no help.

I think because of the equipment on the CLE/EWR leg, the G might indicate that no front cabin seats are available (could G mean gotcha?) and I thought the D class on the Northwest Paris/Detroit leg might mean something like deferred until we can confirm with Northwest (I've seen a notice to that affect when buying a ticket that involves a leg on Alaskan), but I'm a bit reluctant to give up some of our hard-earned miles without knowing just what I am getting, since I noticed that when you buy a first class ticket, but one of the legs is on a plane without first class, they advise you, but apparently give you no break on the price.

When I tried to read the rules associated, all I got was a page saying read the rules associated with all legs, and the lowest class rules apply to the entire ticket, but it would never show me the actual rules.