Those who rush to book a ticket for flights over the Christmas break should not rush. A study by Expedia and the Airlines Reporting Corporation has found that waiting for Sunday is best as that is the day when deals go on sale.

In fact, tickets on Sunday can be 13% cheaper than those bought on a Friday. It is believed that these tickets are cheaper because airlines know that this is when leisure travelers book so they avoid plcing high prices that would put them off. Business travelers, however, can’t help but book their journey through the week, especially on Friday meaning that they would be prepared to pay a higher price in order to get a convenient flight for their business meeting.

Friday is singled out as the most expensive day because airlines typically implement price hikes on this day.

The second-cheapest day for flights is Tuesday because that is the day when airlines weigh up their sales and dump cheap flights onto the market when they find that they haven’t hit targets.

That’s not all! The timing of how much in advance you book your flight is also important to secure a bargain price. The idea is that travel companies set a price and then gradually drop this price as they weigh up how full or empty the flight will be. If the flight is near empty they may drop their prices to rock bottom rates. This works in cases where there are lots of unsold ticket and could go awry if flights are fully booked. In that case, the tickets may be 66% more expensive.

Early birds also manage to get good deals as soon as flights are released. The first few tickets on flights are available at cheaper rates. So sign up to social media and keep an eye out on different destinations to judge when to book.