Although there's no "magic" day or time to find the best airfares, you can save money if you know how to do a flexible date/destination airfare search.
Several years ago, the major online travel agencies (Travelocity, Expedia, etc.) got rid of their flexible travel date calendars. But there are still some great tools, some of them fairly recent additions, that will help you pinpoint when and where it's cheapest to fly.
So here's the Airfarewatchdog.com guide to what you need to know now in order to be a flexible travel date bargain hunter.