Not sure if AC is doing anything, but most US majors, as of yesterday afternoon/evening raised their base fares to the equivalent amount the taxes would have been - essentially meaning the end price to consumers is now the same as it was on Friday night - just the $ that would have gone to the government are going to the carriers. US started immediately - think UA did this sometime yesterday afternoon or evening. Holdouts now are Virgin, Alaska, Frontier and Spirit (if Spirit even counts).