What’s the cheapest day to book flights?

There are, unfortunately, no hard and fast rules that always apply when it comes to the cheapest days to book flights. So many factors go into the cost of flights that it’s hard to know what the prices will be from one hour to the next, let alone on any given day of a single month or over the course of a year.

That said, there are some recognizable patterns when you look at the costs of airfare over a long enough timeline, and there are some studies designed to uncover the cheapest day of the week to book flights. In particular, Expedia’s 2025 Air Travel Hacks Report used actual flight data to help consumers decide on the most affordable times to book airfare or fly the friendly skies within the United States or overseas.

If you’re hoping to save on airfare for your next trip and are curious when you should book or which days of the week to fly, read on to learn more.

Cheapest day of the week to book flights

The cheapest day to pay for airfare can vary from week to week, but Expedia’s report reveals consumers who book airfare on Sundays instead of Mondays or Fridays tend to save approximately 6 percent on domestic flights and 17 percent on international flights. Expedia also notes that Sunday was the cheapest day to book flights in 2021, 2022, 2023 and 2024, although savings rates have varied year to year.

For its report, Expedia used data compiled by the Airlines Reporting Corporation, which has information on 12 billion annual passenger flights operated by more than 480 airlines in over 235 countries.

If you want to save more, you should book domestic flights at least a month in advance to save an average of 25 percent compared to those who booked last minute, according to Expedia.

Meanwhile, booking international airfare between 18 and 29 days before departure tends to yield the lowest prices versus booking three months ahead or more. However, study data shows this can be a “high risk, high reward strategy” since waiting too long could leave you facing sold-out flights, higher prices or flights with suboptimal routing or layovers.

Most affordable day of the week to travel

While booking your flight on a Sunday helps you score the lowest price, flying on a Saturday or Thursday may help you save on airfare. The savings can be as much as 17 percent for domestic flights and 15 percent for international trips.

Interestingly, the most expensive day to fly is Sunday each week whether you’re traveling close to home or jetting off to a far-flung international destination.

Cheapest months to travel

Data from Expedia also shows that March is the most expensive month to travel across the board, followed closely by February. If you want to score some savings, consider traveling in August instead.

Savings can reach 12 percent for domestic airfare when travelers fly in August instead of February. For international trips, savings in August work out to up to 7 percent compared to fares in March.

What factors impact flight prices?

A range of factors can impact the cost of flights, but most of it boils down to supply and demand. For example, costs for airfare tend to be less expensive during off-peak season to any destination, whereas prices surge during peak travel times when demand is higher, such as holidays and the summertime.

Fuel costs can also impact flight costs, along with the cost of labor, labor shortages and other underlying issues for airlines. Ultimately, airlines use complex algorithms to determine pricing for their fares, and these factors are just part of the equation.

Tips for finding cheap flights

To get the best deal on domestic or international airfare in 2025, you’ll want to combine several smart strategies that impact both booking and flying.

• Book airfare on a Sunday. As previously mentioned, booking airfare on Sunday is cheaper than other days of the week, especially Mondays and Fridays.
• Be willing to fly mid-week. Since Thursdays and Saturdays tend to be the cheapest days to fly, see if you can tweak your travel plans so you depart and fly home on these days.
• Consider multiple airports. Kyle Maltz of Dollar Flight Club says you should also be flexible with departure airports and routes. “Expanding your search to nearby airports can definitely yield pricing differences for the flights to the same destination,” he says. “Additionally, flying into alternative airports can help you maximize savings but get you to the same destination.”
• Fly one-way flights instead of round-trip. “This is a great strategy especially if you’re traveling to a location like Europe where it’s very cheap to fly within Europe but generally more expensive getting there,” Maltz advises. “Finding the cheapest location to get you there and then finding a quick flight to your final destination can help you save a solid percentage on overall flight costs for a trip.”
• Set price alerts. Use a tool like the Hopper app to set up price alerts that notify you when airfare prices drop significantly or when their technology says it’s the cheapest day to book. Expedia also offers Price Drop Protection in its app for a fee or for free if you’re a Gold or Platinum tier One Key member. If you book a flight that drops in price later and you have Price Drop Protection, Expedia will refund you the difference.
• Avoid peak travel times. Not only can traveling off-peak help you score significant savings on airfare and hotels, but Expedia data shows that off-peak travel comes with fewer cancelations and delays overall. Booking early morning flights instead of afternoon or evening flights will also make it less likely for you to see delays.
• Use companion passes. Companion passes vary from airline to airline but allow you to earn discounts on a flying companion’s ticket. Some of the best companion passes are offered by Southwest Airlines, Alaska Airlines and British Airways.
• Earn airline miles. Consider signing up for frequent flyer programs that let you book airfare with miles you earn for flying and other activities. You may even be able to earn miles for shopping through an airline shopping portal or signing up for an airline’s dining program.
• Sign up for an airline credit card. You can also start racking up miles for airfare with a co-branded airline credit card or travel credit card. Maltz says this is a great strategy even if you’re not a frequent flyer. “There are amazing limited time offers with travel cards throughout the year that will help you save a ton on your flights and even sometimes cover the cost of flights and hotel stays,” he says.

The bottom line

The cheapest days to book flights may be different from one week to the next, and the same is true for the day you travel. However, taking a full view of the data shows that some travel dates tend to be less expensive on the booking end and the traveling end — at least most of the time.

Arming yourself with this information is one of the best ways to save on airfare over the long run, but it’s not the only way. If you combine savvy shopping with a huge stash of airline miles, you can pay even less for airfare all year long.