Instead, flights tend to be the most inexpensive when you book between four months and three weeks before your departure date. According to CheapAir.com, you can expect rates to go up after that period.1 There may, of course, be some compounding factors that can affect this.

In 2026, the general rule remains that flights are significantly cheaper when booked further in advance, but the "sweet spot" has shifted. For domestic flights, data shows that booking 21 to 45 days out yields the best prices; booking closer than 14 days usually results in a 30–50% price hike as airlines target last-minute business travelers. For international flights, the window is wider, with the best deals found 4 to 6 months before departure. While "last-minute deals" do exist, they are increasingly rare due to the AI-driven "revenue management" software used by 2026 airlines, which is designed to fill every seat at the highest possible price. The only time flights are cheaper "closer" to the date is if a route is significantly undersold, causing the airline to slash prices 48–72 hours before takeoff to recoup costs—but this is a risky gamble that rarely pays off for popular holiday destinations.