Confused by conflicting advice about how and when to book the cheapest flights? Follow the facts instead: Our data-led guide will help you hack the best flight deals for 2025
When it comes to booking flights, it seems like everyone’s an expert. From your mom to online message boards, advice is everywhere on “cheapest days to fly,” the “priciest months to avoid,” and why you should absolutely fly on this day but never on that day. It can all feel confusing, conflicting, and overwhelming.
It’s also often wrong.
We know this because we have exclusive access to some things that can set the record straight: facts. Expedia has partnered with ARC (the Airlines Reporting Corporation) to slice and dice actual data—not theories or hunches or vibes—on trends like the cheapest day to book and travel, the busiest months, and the price spreads between economy and premium.
With this data, we can debunk some myths that are feeding misinformation, causing stress, and nudging you to pay more than you should. And the pro move, of course, is to combine these insights with Expedia’s new Flight Deals app feature, which works tirelessly 24/7 to find you the best deals customized by home airport, travel date, and destination.
The upshot of this data? There are deals to be had, certain months are better than you think, and you can book your next trip armed with real insights—not anxiety.
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Myth: “The earlier you book your flight, the cheaper it will be.” I grew up hearing this advice from my parents, who heard it from their parents, who heard it down the generations, probably since Orville and Wilbur Wright’s parents. But sorry guys, it’s not correct.
Truth: While you probably shouldn’t wait until the very last minute—the data does not endorse the “morning of” plan—you likely have more leeway than you think. According to the data, the magic window to book the cheapest international flights is 18 to 29 days out. (Can’t wait? Expedia’s Price Drop Protection means you’ll be refunded any difference if the fare price falls.)
Myth: “Sunday is the savviest day to travel.” Depending on who you listen to, this myth takes different forms, but a common belief is that it’s best to travel on the weekend so you’re not competing with weekday business travelers. Not according to the data.
Truth: The cheapest day to travel internationally is actually Thursday, and Sunday is the most expensive; this knowledge can save you up to 8%. Of course, for many, potential stress outweighs cost—so if you’re looking for the quietest and calmest experience (rather than the cheapest), shoot for Tuesday. On average, that’s the least crowded day of the week.
Myth: “It doesn’t matter what day you book your ticket.” While the airline algorithms that determine price can seem mysterious and bewildering (another reason to use Expedia’s Flight Deals app feature), there is some method to the madness.
Truth: The data shows that Sunday is historically the cheapest day of the week to sit down and make the purchase, with Friday as the most expensive. Taking advantage of this discrepancy can save you up to 13%.
Myth: “The busiest months to travel are during the holidays.” This myth is deeply ingrained in our culture. And it feels true, because most of us either travel on the holidays or have family who do. An entire genre of movies is even devoted to holiday travel—Planes, Trains and Automobiles, anyone?
Truth: It turns out that the busiest month to fly is not November or December, but actually July, which sees more than double the number of flights than February (the quietest month).
Myth: “July and August are the priciest months to fly.” You might assume, given July is the busiest travel month, that summer is the most expensive time to travel? Not so: Busy doesn’t mean costly.
Truth: For U.S. travelers, the cheapest month for an economy ticket is actually August, and the steepest is March. Looking to upgrade? July is the cheapest month to fly premium, while February is the most expensive. So, on top of the sun and the beach and the warm water, why not travel in the summer and save up to 12%?
Myth: “Flight prices go up every year.” It can certainly feel like the costs of all goods and services just keep inexorably climbing higher. But air travel? For U.S. travelers, it’s bucking these trends and is in fact getting cheaper.
Truth: The price of the average U.S. economy ticket is 2% lower than last year. And the savings are even greater for premium seats: The average price of a U.S. premium ticket is 5% lower than last year. What’s more, the gap between economy and premium is shrinking, meaning it’s no longer as costly to upgrade. The average difference in cost for flying premium vs. economy is 10% smaller than it was in 2019, making now an especially good time to treat yourself with some premium perks. You’ve earned it. (Not a myth.)
Jeff Wilser is the author of seven books, a frequent traveler (living in 24 countries in the three years to 2020), and a contributor to The New York Times, GQ, and Fast Company.
Air Hacks 2025 data for best day of the week to book and depart, cheapest month to travel, price development information, busiest airports, cities with airports trending up and ideal booking window is based on average round-trip ticket prices for January through October 2024, sourced from ARC’s global airline sales database. Flight cancellations and delays data based on January through October 2024 flight status data sourced from OAG’s global flight data platform. Most popular and trending destinations to fly information is based on Expedia’s 2024 flight demand to-date compared to the same period in 2023.
