There's finally a scientific answer to that magic number of days before a flight when tickets are the cheapest.
Analysts at CheapAir spent a year going over more than four million different airline trips and determined that prices are lowest 54 days, on average, before takeoff of domestic flights.
If you can't book 54 days in advance, they recommend staying within the "prime booking window," which is 104 to 29 days before a trip.
Read this article to learn the "magic numbers" for common international destinations.