In the old pre-recession, pre-last-minute-sale days, airlines offered their best fares for tickets booked in advance. Those days — sadly — are back with a vengeance.

Most airlines will tell you they require a 14-day advance purchase on their sale fares. With a heartier economy and less competition in the skies, I’m finding that after the 21-day mark, fares go up substantially.

On American, prices can jump as much as 30 percent on that magic day between the 21-day advance and the 20-day advance. And the prices go up again at the 14-day mark.

Another change for AA fliers: The “free hold for 24 hours” function used to hold the price until 11 p.m. the next day. Now that function is “up to” 24 hours…which means after a much briefer period you can find that your great fare has skyrocketed. Beware.