Travelocity analyzed the cheapest days to fly over both Christmas and New Year’s and found that many itineraries dipped well below the average cost of a holiday flight ($421) when travelers adjusted their departure and return dates. Sunday flights are the most expensive for both holidays, meaning travelers need to avoid Dec. 26 and Jan. 2.

Christmas Travel

For Christmas, Travelocity’s cheap flights analysis shows the lowest average itinerary is $351, a notable $70 lower than the holiday average, departing on Christmas Day and returning the following Tuesday (Dec. 28). Christmas Eve and Christmas Day are among the cheapest days to fly.

New Year’s Travel

Travelocity’s cheap flights analysis for New Year’s shows that if travelers delay their returns until the Monday after the holiday (Jan. 3), the average fare could drop as low as $344 roundtrip. Because many travelers add a hotel stay to their New Year’s plans, considering a flight plus hotel vacation package may offer even greater savings. A separate Travelocity study showed travelers can save up to $525 per couple just by booking their flight and hotel together.

Travelocity reminds travelers that planes are expected to fly 90 percent full throughout the holidays, which means consumers need to book in advance to get an affordable fare and their choice itineraries. With the 21-day advance purchase window for the Christmas holiday ending in a few short days, travelers need to book ASAP.

“The age-old advice to book as far in advance as possible still holds true, especially during peak travel periods,” Genevieve Shaw Brown, Travelocity senior editor, said. “If Thanksgiving travel was an indication of what’s to come, the remainder of the holiday season means more travelers and less time to dilly-dally on that booking.”