I know for a fact that the following applies at Delta, and I fairly certain it also applies at NWA (and perhaps some other US majors) so here goes:

A friend that's a Delta 757/767 FO told me the other day that due to the realities of the post 9/11 world where they have too many pilots and not enough flights Delta is offering its pilots these three major options as far as bidding for monthly schedules (or "lines") goes:
1. Bid for an actual scheduled line and get paid for a guaranteed minimum of about 78 hours of flight time, or
2. Bid for a "Reserve" line for a guaranteed minimum of 70 hours of pay where the pilot is essentially on call or the beeper for a large part of the month in case if another pilot calls in sick etc, or
3. Bid for a line where they are paid for 55 hours (and remember that almost all remaining non-furloughed Delta pilots make well in excess of $100/hour, some much more than double that) FOR DOING ABSOLUTELY NOTHING, i.e. stay at home and don't show their face for a month since Delta doesn't have any work for them!

Apparently alot of pilots are asking themselves, "Why bust my a** for 78 hours pay (or 70 hours if on Reserve) when I can do absolutely nothing and still get paid for 55 hours?" Since everything for pilots is based on seniority my Delta friend said the very most senior guys are the ones that are always winning these coveted 55 hour lines for doing absolutely nothing. On top of this some of these pilots also fly in the Air National Guard or Reserve - they can easily take home $6K/mo in taxes from Uncle Sam while at the same time pocketing big bucks for not showing their faces at Delta for a month.

And we wonder why the some of the major airlines are doing so poorly...