'Tis the season to start thinking about where to spend the holidays. Expedia.com flight data released today shows the cheapest time to book flights for Thanksgiving travel is 31-90 days out, and 21-30 days out for Christmas. Travelers who booked during these windows in 2017 saved an average of 10 percent on holiday fares, and with Expedia's travel sale running September 14 – 17, it's a fantastic time to lock in travel plans through the end of the year.

"The busiest travel season of the year is right around the corner, and data shows us that early planning helps travelers save – especially on airfare," said John Morrey, SVP Brand Expedia. "We like to inform travelers of these sweet spots so they can book confidently and maximize their savings ahead of the holidays."

Best Time to Buy Flights

According to Expedia data, flights booked in September and October can yield significant savings for Thanksgiving travel, while the best time to lock in Christmas travel plans is typically November.

• Thanksgiving: For 2018 the optimal window to book and save is now through October 22

• Christmas: For 2018 the optimal window to book and save is October 26 through December 4

The holidays are not the time to procrastinate, at least where airfare is concerned. Travelers who waited until the last minute, zero to six days out, paid the most – 10 to 20 percent above the average ticket price.

Best Time to Book Hotels

Travelers have more flexibility when it comes to finding a hotel for the holidays. According to Expedia data, booking a hotel closer to your trip, zero to six days out, could save travelers 20 to 30 percent. This is an instance where waiting until the last minute can result in a lower average daily rate as some hoteliers aim to fill unsold rooms.

Waiting until the last minute to book a hotel may be a little nerve-racking. For those who like to plan ahead but still crave the savings, consider using the Expedia Add-On Advantage to get guaranteed savings on your hotel reservation during the holidays. Adding a hotel on to a reservation (flight, car, etc.) will then unlock discounts up to 43 percent off select hotels. Just make sure you book and attach the hotel to your existing itinerary at any time before the start of your trip.

Save Up to 90 Percent with Expedia's Upcoming Travel Sale

Get ready for Expedia's Really Big Travel Sale – featuring hundreds of amazing deals on hotels, flights, packages and more!

• 90 percent off select hotels on the Expedia App with coupon (Expedia Member-exclusive)

• $750 off $1,000 flight + hotel package coupon (Expedia Member-exclusive)

• 75 percent off select hotels with coupon (Expedia App-exclusive)

• 50 percent off select hotels on Expedia.com with coupon

• $500 off $1,000 flight + hotel package coupon

• 10 percent of select hotels on Expedia.com with coupon

• Book a cruise and get up to $1,000 to spend onboard

• Up to 30 percent off Things to Do