I was looking through several fleets' e-bids tonight, trying to decide which fleet to bid when I go back. The monthly e-bids are easier to read, to me, than the other traditional type.

There is a column, just prior to "Layovers" (or similar; I don't have it displayed at the moment). It has no title. I can't find a legend that tells what the codes are.

The column shows one of four letters: A, P, D, and H. I find it in most fleets in IAH, but not the A-320, which only shows "D."

I started to think it meant "Atlantic," "Pacific," "Domestic," and "Hawaii," but it doesn't seem to match-up: South America was shown as "D." It might mean "Time Zone," as South America trips would generally be the same as the US time-zones (within an hour or two, so kind of like flying Domestic).

I looked in the other version of the bids, but I couldn't find a comparable letter-match.

Any insight appreciated.