UPDATE: For the latest research on the Best Time to Buy Flights, visit our new airfare study: The Best Time to Buy Flights in 2022.

Every year at CheapAir we go through a little exercise.

When to Buy Flights

We take a list of the top 15,000 markets where our customers live and like to fly to, and we watch fares between those cities over the course of an entire year.

It’s actually more than a “little” exercise. In 2014, it amassed to 1.5 billion airfares as we watched 4,986,522 trips, recording the lowest fare for each trip every day from 320 days in advance up until one day before flight time. It’s a treasure trove of cool info if you’re an airfare geek; or, a curious use of terabytes, if you’re anybody else.

Since the majority of questions we get asked every year start with “When is the best time to book my flight to…”, the first thing we always do with this data is determine, on average, how far in advance should you book your flight to get the lowest fare.

This year, for domestic flights, the answer is 47 days.


Now, if our database could talk, it might protest having to give just one number for when to buy. As we have found in years past, the average is just that: The Average. There was, and always will be, quite a variance across the five million trips we reviewed.

Here’s an example: If you happened to fly from Boston to Detroit for a seven day trip starting on February 13, there were actually some fantastic (and rare) last minute sales. In that case, booking the day before the flight was the best day to book. This is extremely rare, and waiting until the day before travel is something we never advise. At the other extreme, there were trips like Austin to Orlando, leaving on July 11 where your best bet would have been to buy 320 days in advance.

The point is, for individual trips, the best time to buy varies substantially depending on the destination, time of year, and travel days. So think of 47 days as a guide, not an exact day you should book. And on average, booking later than 47 days will always carry more risk than booking early.

Here are 5 additional pieces of advice that we are able to glean from this massive study. Keep in mind that our focus here is on domestic flights – those within the U.S. Click here for our discoveries about the best time to buy international flights.

1. When You Buy Matters

A graph of the best fare by the numbers of days booked in advance looks deceptively smooth, aside from the sharp rise once you get inside 14 days. At 320 days out when we started looking, average fares were about $50 higher than their low point. Prices dropped gradually until 47 days out (the bottom) and after that they started to rise again slowly. Once inside of 14 days they shot up pretty significantly.

But the smoothness of this graph belies the true volatility of the market. It looks smooth only because we are aggregating such a large number of individual trips. The spikes and dips even out over such a large dataset. But our study confirms that the price volatility when buying an airline ticket is more like buying a share of stock than buying something at Target. The lowest possible prices change on average 70 times during the booking window we looked at – that’s once every 4 ½ days! And even if we ignore the super-pricey booking period of within 14 days, the average difference between the best low fare and the worst low fare was a whopping $201 during the time a trip was available for sale! So the date you pick to book your flight absolutely makes a huge difference.

2. Waiting for Last Minute Deals is a Bad Idea

The easiest and most obvious conclusion we can draw is that you should buy your ticket at least 14 days in advance. The Boston to Detroit example above was an outlier. Fares are almost always more expensive at the last minute. Tickets purchased within 14 days were $111 more, on average, than those purchased further in advance; tickets purchased within seven days were $174 more. So don’t believe the myth that never seems to die that a day before flight time airlines will practically give away their unsold seats. That doesn’t happen. Give yourself 14 days advance purchase at the very least; or better yet, 21 if you can swing it.

3. Be Careful Not to Book Too Early

In years past when we looked at numbers we came to the conclusion that the worst thing you could do was to buy your ticket too late but the second worst thing you could do was to buy your ticket too early. That’s still true, but the “penalty” for buying a ticket too early is less significant than in years past.

Airlines have historically come out with really high fares when flights open for sale, let them sit for a while, and then introduce various sales a few months before flight time in a mad scramble to fill all the empty seats. But with Delta having swallowed up Northwest, United merging with Continental, Southwest buying AirTran and now American combining with US Airways, there is less competition and less capacity. Airlines don’t have to do as much scrambling. Fares still tend to be lower a few months before travel than they are 11 months before travel, but that difference is not as pronounced as it used to be. Still, on average, domestic flights open up for sale about $50 higher than their ultimate lowest price – and they typically stay that way for many months.

4. One to Four Months Out is the “Prime Booking Window”

The general pattern is that from the time a flight opens for sale, fares will drop slowly but steadily until reaching a low point somewhere between 27 days and 114 days out. That three month window, which is essentially between one and four months in advance, is what we call the “prime booking window”. Much more often than not, the best fare for a domestic trip will be offered at some point during that window.

If you don’t book within this window, it is generally better to book too early than too late. Those booking more than 114 days out paid an average of $32 more for their flight in 2014; those booking inside 27 days paid an average of $47 more (and a lot more than that if within 14 days).

5. For Summer and Holiday Travel, the Rules are a Little Different

There are important exceptions to these patterns, mostly for very popular routes during very popular times where flights tend to fill up quickly and the most optimal time to buy tends to be earlier than the normal one to four months. Hawaii is a great example; the best time to buy flights to Hawaii is usually pretty close to the time they go on sale (11 months in advance). Flights around Christmas and Thanksgiving, and warm weather trips for Spring Break, also have a different dynamic and you’re generally better off booking sooner rather than later.

In 2014, demand for air travel continued to increase and airlines kept supply in check for the whole summer. June to August began to look a lot like the special holiday seasons. For summer travel last year, the best time to book was 76 days in advance on average – almost a month earlier than the rest of the year. And the danger in booking too early was much less pronounced. Fares booked 320 days in advance were, on average, only $8 more than their low point. More than ever before, air travel has become a seller’s market, especially in the peak seasons, and the airlines don’t have to be as aggressive as they used to in order to fill all their seats. This means that the deals you see early on for peak season flights are increasingly likely to be among the best deals that will be offered.


But It’s Not Just About Price…

It’s important to understand something about our methodology. For every booking date for every trip, we simply looked at the lowest possible fare that would have gotten you there, without regard to airlines, flight times, or number of stops. Sometimes, there are differences in the quality of flights or choices of flights that are not reflected in our numbers. For instance, there might be a situation where 80 days before a trip from L.A. to New York there were eight non-stop and 24 one-stop flight options for $350. 30 days before that same trip there might have been just one flight left at $350, a one-stop flight at 6:00am with a 2 ½ hour layover in Chicago. Based on our methodology, each of the two scenarios has the same low fare so we would have treated both as equal – and our numbers would suggest you are in a good position to wait. In reality? You would have been much better off booking 80 days out.

No matter where you’re going, it’s a pretty fair assumption that the number of options (and, therefore, the quality of those options) is highest the earlier you book. This is important for flyers who care a lot about specific flights, specific flight times, specific routes, or specific airlines. The less flexible you are with respect to these parameters, the more we advise you to book earlier than we would otherwise suggest to make sure you can get a flight that is satisfactory.

Some Additional Tips for Finding the Best Air Fares

Given everything that we’ve learned, here is some general advice on how to go about your airfare search:

– Since it’s impossible to know exactly the best day to buy an airline ticket, the best strategy is to check fares early and often. For travel during the summer or holidays, start your research as soon as you can. For other travel dates, try to check frequently in the one to four month lead-up to your travel dates. By checking often enough, you are likely to see both the ups and the downs as fares fluctuate– and you’ll be able to tell the difference and recognize a good deal.

– Aim for a good deal, not the best deal. With 70 different fare changes on average for each trip, you have to get very lucky to book your flight at their absolute rock bottom. So don’t get too caught up in trying to squeeze a few extra dollars off your ticket price. When you see a good deal, grab it since any good fare is much more likely to go up than down.

– Consider booking much earlier than the 47 days in advance if: (1) you are traveling for a holiday; (2) you are traveling during the summer; (3) you are traveling with a family or large party (three or more travelers); (4) or, you are particular about your airline, number of stops, travel times, or seat assignments and you see only a few flights offered that you’d be happy with.

– Avoid booking too early (before four months) if all of these are true: (1) you are not traveling during the summer or for a holiday; (2) you are traveling by yourself; (3) and, you’re flexible on the airline and flight times.

Final Shameless Plug

And, finally, having reached a limit on the number of words we can write without shamelessly plugging our own web site, consider CheapAir’s unique Price Drop Payback option as a way to make the ticket buying process less stressful. If you purchase with CheapAir.com we provide price protection for free – if you see a fare drop after your purchase you can get a travel credit back for the difference, up to $100 per passenger. That’s something that no other online travel agency provides and, in the crazy world of airline pricing, allows you to buy with more confidence!

Start your flight search


  1. hello, I am looking 4 ticket from SFO ( or any nearby airports) to FLL (Florida) from Aug 2-Aug 12. We are flexible +/- 1 day for departure. For returning flight we need flight out after 11 am as we are returning from a cruise. The price was around 380 in Jan and Feb. I am checking it now and the price is up to 430 or so and seems to continue to go up. Should I book it now or wait for the prime booking window?

    • Hi Thao, Because you’ve mentioned that the fare is continuing to climb I would definitely not wait to book. Itineraries that require specific flights for cruises do tend to sell out faster so the lower fares tend to go first.

  2. Hi, We are traveling to Barcelona from may 26-June 9, 2018. Should I wait a few months to buy airline tickets?

    • Hi Jacqueline, Definitely not! Barcelona is very popular in the summer months and to get the best fares you would not be shopping too early if you look now. If your gateway is going to be NYC or Atlanta or Los Angeles, you might find better fares a bit closer to your travel dates, but don’t bank on it. Airfare from May to August is already priced at a premium and once the lowest fares on a flight sell out, they typically do not return. I just saw that you’re leaving from Phoenix. I might price out separate tickets from PHX to NYC and then from NYC to Barcelona to see if there might be any savings in pricing tickets separately. Sometimes this can save you quite a bit if price is your main deciding factor. Keep in mind if you’ve bought 2 tickets though, that you can;t check bags all the way through.

    • Hi Jane, What city are you traveling from? The very good news for you is that you’re traveling well into the shoulder season for Italian/European destinations, so fares should be reasonable.

  3. Hi,
    I am trying to book a round trip ticket to Mumbai from Los Angeles. When do u think should I book my tickets or what is the best fare i could get. I am planning to leave on Dec 16 to Jan 20. The dates can vary a little bit up and down. should i buy the tickets this early or wait?

  4. I’m planning a trip to Ireland. I would be leaving from Hartford on/around June 15th and returning August 17th. Not sure if I should buy the tickets now or wait until a closer date ??

    • Hi Kirsten, Most people want nonstop flights and you can get a decent priced airfare from Hartford right now for about $700 on Aer Lingus to Dublin (not sure if that’s where you were hoping to fly, but it’s going to give us the best fares. You can do about $100 cheaper if you fly out of JFK (probably not worth the hassle and gas money). In the summer, $700 is really a good price for Ireland (you can probably find a flight out of Hartford in the fall in the $500-650 range, but there’s no way the fares in June are going to go down (and they’ll almost certainly go up). Buy soon.

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