You hear all sorts of vague theories about the best time to book plane tickets to get the best deal . . . so it's nice to see a study like this that eliminates the fuzziness and just gets to the damn point.
A website called CheapAir.com monitored prices for FOUR MILLION flights last year, and found the absolute BEST time to buy a plane ticket is . . . exactly 54 DAYS before your trip.
Any earlier or later than that and you're looking at a higher price . . . although they say it's generally better to buy earlier rather than later.
That 54-day mark is for domestic U.S. flights. If you're going to Mexico, book 89 days in advance . . . 101 days in advance for the Caribbean . . . 129 days in advance for Asia . . . and 151 days in advance for Europe.
The only time the 54-day window doesn't apply is for Christmas or Thanksgiving flights. You're best off booking those SIX MONTHS before . . . on June 4th.