Thinking of doing some flying soon?

You really can save some serious money if you book your flight in advance. The secret is to know exactly when to buy your plane tickets.

I'm sure you have a few so called travel experts in your life, who are more than happy to give you their various theories on when is the perfect time to book your flight to get the best deal. Well lucky for you, there is finally a website that monitored the prices for four million flights last year, and they found the absolute best time to buy a plane ticket.

The website is called CheapAir.com and what they found is the magic number to save money when booking a domestic plane ticket in the U.S. is exactly 54 days before you fly.

Any earlier or later than that and you're looking at paying a higher price. Although they say it's generally better to buy earlier than later.

The 54-day mark is the ticket to saving money for domestic U.S. flights. If you plan on going south of the border to say Mexico, you'll want to book 89 days in advance.

Thinking of a Caribbean vacation later this summer, plan on making your reservations 101 days out to get the best deal. You'll want to book 129 days in advance for Asia and if you're planning a European getaway anytime soon, you will want to get in touch with your travel agent 151 days before you decide to leave.

You should know, the only time that 54-day window doesn't apply supposedly, is for Christmas and Thanksgiving flights. If you plan on doing some air travel over the holiday's this year, you need to book your reservations on June 4th. No earlier and no later.