It's Christmas day in less than a week, and for sure, all holiday air travelers have bought their tickets by now. Agree? Well, most people have but procrastinators always exist. If you are one of them or just curious for a friend, what would you do being too late in the game?

First and foremost, know that you are not alone. About 75 percent of would-be travelers complete their holiday ticket booking by December 7 in a typical year, says Orbitz spokeswoman, Jeanenne Tornatore. That means almost a quarter of all travelers book airline tickets at the site within three weeks before Christmas Day, USA Today reported.

For New Year trip, travelers wait a bit longer. It is not until December 21 that travelers typically complete their ticket booking for that season, Orbitz added. However, with the clock ticking, it's time to finalize your plans especially if you are among the stragglers for a merry Christmas trip. While keeping in mind that the most affordable airline tickets have probably disappeared already, these few tips could help you avoid paying too much.

Look for the Left-Overs or Off-Peak Days

Flying in December 26 and 27 for a cheaper cost might be impossible if you haven't booked your ticket earlier. Certainly, the cheapest fares for that Christmas travel rush have long sold out. If you are looking for bargains, they will likely come on days less common with most holiday travelers. Traveling on Christmas Eve (December 25) could help knock down your fare.

Off-Peak Flights

Most of the time, a 6 AM departure time is what people avoid the most. Taking those flights may help you save dollars since those flights most likely to have remaining empty seats. Out of the way connections, red-eye flights and long layovers may also give you lower fares in return.

Remember Alternate Airports

If you are flying to San Francisco, remember that San Francisco International airport is the city's busiest, and therefore most expensive. Don't forget to check flights to airports nearby like San Jose or Oakland. Same applies to other countries as well. There is no guarantee that there will be cheaper ticket at an alternate airport, but going beyond your usual search will definitely increase your chances. (Read more tips here.)