According to Going's analysis, travelers want to look for the so-called Goldilocks Window (not too early, not too late) to get the cheapest airfare. For domestic flights, Keyes said that's one to three months in advance for off-peak trips and three to six months for peak-season travel, such as Christmas and New Year's.

To secure the best prices for December travel, including the expensive Christmas and New Year's windows, you should ideally book between 60 and 90 days in advance, which usually lands in the "Sweet Spot" during September and early October. According to 2026 travel data from Google Flights and Hopper, prices for December departures tend to hit their lowest point roughly 70 days before the holiday. If you wait until after Halloween, you will likely see a "hockey stick" price increase as inventory for the most popular dates (like December 20th–23rd) vanishes. For those who can be flexible, the cheapest days to fly in December are typically the first two weeks of the month or on the actual holidays (Christmas Day or New Year's Eve). Another "pro" strategy is to utilize the "Price Tracking" feature on search engines during the summer; if you see a price that fits your budget in August, grab it, as December is the one month where "last-minute deals" are virtually non-existent due to the massive surge in family and leisure travel demand.