Holiday travel can be hectic and expensive if you wait until the last minute to book. Here are expert tips on when to book your plane tickets to score the best deals for the holidays.

If you're planning on traveling this holiday season, book your flights now. The travel surge that started in summer is expected to continue through the end of this year, with significant travel (specifically domestic travel) expected for Thanksgiving and Christmas, according to a survey by consulting firm Oliver Wyman. The survey reports that international travel continues to be impacted, with 67 percent of United States travelers choosing a domestic destination for their next trip over an international one.

Airports are notorious for being packed during the holidays, with 2 million passengers predicted to pass through airports this holiday season, according to Hopper's 2021 Holiday Travel Guide. Wherever you're choosing to go for the holidays, booking early could make the difference between a happy holiday and a stressful (and more expensive) one. Here are pro tips on when to book your tickets for the best airline prices for the holidays.

Book your holiday travel by the end of October for the best prices

The short answer on the best time to book tickets is ASAP to save money on holiday travel. But vacation times and holidays can be hard to plan, so in general, aim to book flights for travel during Thanksgiving and Christmas by October 31.

"After Halloween, prices will increase considerably as Thanksgiving gets closer," says Phil Dengler, travel expert and co-owner of travel resource site The Vacationer. Domestic flight prices can spike 40 percent—about $400 per round trip—from the end of October to the week before Thanksgiving, according to Adit Damodaran, economist at Hopper. "In general, booking domestic flights three weeks in advance (or by Thanksgiving at the latest), should help travelers avoid the biggest price spikes," explains Damodaran.

The day of the week you book tickets can make a difference, too. Book your tickets in the middle of the week for lower prices. "The best time to book airfare is usually mid-week—less people are searching for flights so they tend to dip from Tuesday to end of Wednesday," says money-saving expert Andrea Woroch. But flight prices during holiday season will get more expensive the longer you wait regardless of which day of the week you buy them—so book as soon as you can.

"If you aren't sure exactly what your plans are, you may be able to book a portion of your flight to get the best deal on at least one leg of your trip," says Woroch. According to Damodaran, waiting until the last week for both Thanksgiving and Christmas can cost over $500 round-trip.

Fly on the holiday to save more money

Another way to find cheaper prices on plane tickets is to fly on the day of the holiday. Based on the past two years of Thanksgiving travel, you can save about $50 if you fly on Thanksgiving day instead of the day before, according to travel search site KAYAK.

"Ultimately, it requires a bit of searching, so review airfare prices based on a 30-day schedule to find the best deal," says Woroch. Being flexible with your travel dates can be helpful in finding cheaper prices on airfare: "It's better to be open to traveling based on when you can score cheaper airline tickets, which will fall ahead or before a holiday," she adds.

The day after a holiday can be a lot pricier for return flights. This year, the Sundays after both Thanksgiving and Christmas are expected to be the most expensive dates for both domestic and international flights, according to Damodaran.

Track flight prices in advance to find the best deals

Doing your research, comparing flight deals, and being on the lookout for when prices drop is key for finding reasonable airfare for holiday travel. One way to do this is to monitor flight prices using a tracker such as Google Flights, Hopper, or Skyscanner, which will alert you with deals for your route.

"Set your desired route and travel dates and receive alerts when prices drop," says Janet Semenova, co-founder of travel company Boutique Travel Advisors. "Purchase flights immediately when they reach your desired threshold," she adds. Semenova recommends setting multiple alerts and being flexible with your travel dates. Even if you aren't entirely sure about your itinerary, start tracking flight prices for your route early—and book when you find the lowest price to save money on your holiday travel.