Ever wondered if there’s a magic number of days before a flight when tickets are at their cheapest? FlipFares has an answer for that. Fifty-four days before takeoff is, on average, when flights within the continental U.S. are at their absolute lowest price. And if you don’t hit 54 days on the head, you should usually book between 105 to 21 days before your trip ? within a so-called “prime booking window” ? for the lowest possible prices. In this period, ticket prices typically hover near the lowest price they’ll ever reach. By offering various other services including the accommodation, car rental and train booking services, Flipfares is in a unique position to devise a low-cost travel budget for you.