Seems like they smell Southwest coming. From the WSJ:

Alaska Airlines, hoping to solidify customer loyalty at a time when discount carriers are grabbing market share, is embarking on an overhaul of its pricing structure.

The exercise includes cutting its highest fares, compressing the difference between its highest and lowest fares, and getting rid of the unpopular weekend-stay requirement, according to Gregg Saretsky, executive vice president of marketing.

The carrier, a unit of Seattle-based Alaska Air Group Inc., said the initiative signals the retirement of its "random and lame-brained fare generator" that gouges passengers on the high end and ruins their weekends on the low. "Consumers are voting with their feet and going for simpler fare structures," Mr. Saretsky said. "We want to be the hero before we're forced to because some low-cost carrier plunked down in our back yard."