Several factors affect the cost of airfare — destination, demand, time of year — and they often change. Understanding these indicators is key to booking flights at the cheapest time and flying on the cheapest days.
To help you find the best days to book (and travel), I analyzed KAYAK’s data on one-way and round-trip flights, both domestic and international. The findings reveal that while there isn’t a single best day to book, flying on certain days can save you money.
In this article
The best day to book flights
When to fly domestically?
When to travel internationally?
Tools to help you find the best time to book
Best time to book FAQs
When is the best time to book a flight?
While the data isn’t concrete, it does suggest a few trends for which time might be the best to book flights. But instead of a particular day of the week, it’s about timing.
- For domestic flights, buy flights around 30 days ahead of departure to score the lowest average price, at $228.
- The best time to book international flights, meanwhile, turned up a bit of a surprise. According to the data, the best time to book an international flight is 1 – 2 weeks ahead of time, at an average cost of $666. Proceed with caution!
Good news for when wanderlust strikes at the last minute.
| Trip type | Best time to book a flight | Considerations |
|---|---|---|
| Domestic | 21–30 days out | Booking too early or last minute tends to cost more |
| International | 7–14 days out | Booking too early or at the last minute tends to cost more |
What about during busy travel periods?
Popular travel periods tend to mean higher fares. Book flights early when you can for:
- Summer vacation (June-August)
- Thanksgiving week (especially Wednesday before and Sunday after)
- Christmas through New Year’s
- Spring break
- Three-day holiday weekends (Memorial Day, Labor Day, etc.)
What are the cheapest days to fly domestic?
- Cheapest day to fly out: Monday (~$265)
- Cheapest day to return: Wednesday (~$194)
Overall, you’ll get slightly cheaper outbound fares by flying early in the week, but the real win is returning midweek, where savings are more considerable. One-way flights are also cheaper midweek. Avoid Friday or Sunday returns, when prices tend to be more expensive.
What are the cheapest days to fly international?
- Cheapest day to fly out: Wednesday (~$747)
- Cheapest day to return: Wednesday (~$604)
For International travel, Wednesday offers the best deals. Apart from one-way flights, which are cheapest by a slight margin on Mondays.
Like domestic travel, midweek flying is, on average, slightly more cost-effective than weekend flying. As you might expect, Friday–Saturday flights are the most expensive (especially return flights).
What else to know about the best dates to book travel?
Airfares fluctuate for all kinds of reasons, and KAYAK’s data is merely a reflection of overall trends. That said, no matter when you fly, KAYAK can help you fin the best deals. As an award winning metsearch engine, KAYAK does the work for you.
So even if your travel plans don’t always allow you to book on days with the lowest airfares, KAYAK can help you find a airfare that’s affordable for you, whether you’re looking to explore the U.S. or see the rest of the world.
Monthly best priced flight routes from your home airport in March.
KAYAK tools to help you find the cheapest time to book and fly.
KAYAK offers a variety of Flight Filters to customize your search, including a price filter to keep your budget in line. That’s not enough to determine the cheapest time to buy flights, though, so there are plenty more free tools to help you get there.
- KAYAK Price Alerts: Know when prices go up or down with Price Alerts. Set alerts for specific routes and receive email or phone notifications when prices drop. Run a flight search and try it now.
- KAYAK Price Forecast: Find this tool when you run a flight search on KAYAK. Price Forecast analyzes historical data to predict whether prices on your route are likely to rise or fall, helping you decide whether to book now or wait.
- Flexible date search: Use KAYAK’s flight search calendar to compare prices ±3 days from your selected travel dates, full weekends, or entire months. Green indicates cheaper.
- KAYAK Explore: Don’t mind where you travel to? See which destinations are cheapest to fly to from your home airport using KAYAK Explore.
For best results, set any alerts 2-4 months before your intended travel dates. When you see a price that meets your budget, book it – waiting for a lower fare that may never come can backfire.
Didn’t find what you were looking for? Ask KAYAK.ai
Best time to book flights: FAQ
Every airline’s goal is to get the most money possible for each seat sold, which means airfare pricing is one of the purest examples of supply and demand in action. To do this, popular leisure routes and economy cabins are priced high further in advance, which is when vacation travelers tend to book.
These seats tend to go down over time as the airline tries to fill the flight before departure. Business routes and premium cabins (business/first) are priced lower upfront to fill minimum quotas, then hiked over time as corporate travelers, who tend to book closer to their trips, scramble to get a remaining seat.
The oft-repeated theory that it’s cheaper to purchase airfare on Tuesdays is simply not true. We analyzed airline price trends every day of the week and busted this myth with the discovery that observing demand trends over time was far more important than booking on a specific day of the week.
The cheapest days to fly are the days when fewer other travelers are flying. Friday and Sunday are heavily traveled for weekend events and getaways, but Tuesday and Wednesday are the least traveled and tend to be the cheapest.
However, our latest data turned up some interesting trends regarding international airfare. We found that the cheapest time to book a flight outside the U.S. was about a week in advance, so keep an eye out for last-minute deals (or set a Price Alert).
This is more common in economy class cabins and on leisure travel routes (i.e., vacation destinations). For business class and first class seats, or routes are frequented by corporate travelers, the reverse is more often true, with prices increasing as the departure approaches.
The short answer here can be frustratingly unhelpful: Flight prices change as often as airlines see fit. As the flight fills up (or doesn’t), airlines will continuously change prices to maximize their potential profit, which means fares may not only change daily but can even multiple times throughout the day. Flight prices vary as well depending on the season, the seats you want to book and ultimately the balance between supply and demand of seats.
Sometimes. Airfare prices change regularly based on supply and demand, and the airline’s resulting prediction of how it can maximize income on remaining seats. Computer software is often in charge of analyzing this and updating fares. This can certainly happen at night, but it is equally like to happen any time of day, any day of the week.
Average flight prices of economy class per day of the week and for each 7 – 183 search days ahead of departure in 2026 for round-trips broken down by departures and returns aggregated for domestic and international routes, respectively. KAYAK analyzed search data conducted on kayak.com between 01/01/2025 – 18/03/2026 for traveling anytime until 30/06/2026
