How Far Ahead to Book a Flight

The booking windows that produce the lowest fares for domestic and international travel, and when booking early backfires.

By WarBird Flight editors · Updated September 15, 2026 · 2 min read

Domestic: three to eight weeks

For flights within the US and to Canada, the lowest fares usually appear between three and eight weeks before departure. Inside two weeks, prices climb as airlines sell remaining seats to last-minute business travelers. More than four months out, the cheapest fare buckets are often not yet open.

International: two to five months

Long-haul fares are released earlier and sell more predictably. Two to five months ahead captures most of the savings; for summer travel to Europe or December travel to South Asia, book at the early end of that range or sooner.

Holidays: as early as possible

Thanksgiving, Christmas, and spring break do not follow the normal curve. Fares only go up as the date approaches, so book as soon as your dates are firm, ideally by early October for Thanksgiving and Christmas.

Why the curve is U-shaped

Fares are not a straight line from high to low. Months out, only the pricier fare buckets are loaded, so the fare is high. As the flight fills to a normal level the airline releases its cheapest buckets, and the fare bottoms out in the three-to-eight-week window. Then, as the last seats sell to travelers who have to be on that flight, the cheap buckets close and the fare climbs steeply. Booking too early and booking too late both land you on the expensive side of that curve.

Flexibility widens the window

The booking windows above assume fixed dates. If you can move a day in either direction, you get more chances to catch a cheap bucket, because the low fare rarely lands on every day at once. Tell the agent your date range rather than a single day; on our own fare data the cheapest departure in a three-day window is often 15 to 30 percent below the most expensive day in it.

Watch, do not gamble

Once a fare is in the normal low range for its route, waiting for a further drop usually costs more than it saves, because the next move is more often up than down. A price alert is useful for spotting a genuine sale, but if a fare already looks good for the season and route, book it. An agent who tracks the route can tell you whether the current number is actually low or just average.

When early booking backfires

Booking a non-refundable fare six months out and then changing plans is the common mistake. Standard economy fares on US carriers can be changed without a fee, so if plans might move, buy that rather than basic economy.