I am new to all of this. My question is about the various letter codes used to describe the type of fare. I have figured out that this is especially important when wanting to either purchase (with miles) or requesting a complimentary upgrade to first.
I am with Delta and Continental. How do I know what fare i am purchasing? I normally purcase directly from the airline site (for the bonus miles) or from travelocity or similar.. If i wanted to purchase a specific type of fair, how to I request that??