They're using browser cookies. If you have another browser (Firefox, Chrome) check again or use private browsing. I was shopping award travel for hotels and went back the next day and got much higher quotes; changing browsers got me back to original. Common practice used by sites like Expedia and Travelocity as well. Don't know if it's supposed to be an incentive to book now or if the psychology is that when you come back you've already made the buying decision and won't go back to shopping around...