Originally Posted by
CO 1E
Under the GSA travel arrangements, there are two types for general governement travel, capacity controlled (the equivalent of a mid to low-range coach fare, depending on airline) and non-capacity controlled, which book into Y on most carriers. On CO, I believe non-capacity controlled used to book into H (now B), but I do not know what the current status of that is since CO does not have many GSA city pairs these days.
Other agencies may have access to other types of government fare availability, also.
CO has no GSA city pairs this year, though one can still book government fares with them. The fare classes range and I frequently see B or Y (sometimes K).