We’ve been in the airfare prediction game for many years, and we put out a Domestic Annual Report and International Annual Report that helps many consumers get the best airline ticket price. This year, because of unprecedented demand vs. capacity issues, and a general “wild west” vibe when it comes to airfare, we thought it might be a good time to chat about Advance Purchase deadlines. Put simply, these are the points in time where the airlines almost always bump up the prices of your flight. The closer you get to your flight date, the higher the price you’ll pay. But we know when those cutoff points occur. And now, so can you!

How does the airline know when to hike your airfare?

In the past, the airfare increases were mostly handled by machine algorithms. If you’re interested in a deep dive on pricing algorithms, check out this post. But, we digress. The airlines use automated systems designed to charge you more, and maximize their profits. More on that in a bit.

Wait! Shouldn’t empty airline seats go on sale if they aren’t sold?

This does seem logical. After all, in a lot of other industries, if no one is buying, the vendor starts to slash prices. But the airline industry operates differently. First, the airlines like to set aside a certain number of seats on a flight for departure day that they can upsell. People sometimes show up on their travel day willing to splurge a little for an upgrade. Also, rewards program members are often given those extra seats as free upgrades. The airlines have a number of seats they’re prepared to let sit empty all the way up to departure day. If they can sell some of them at a premium, so be it!

It’s definitely something of a unicorn that last minute flights go on fire sale. It simply doesn’t exist in modern commercial air travel.

What are the cutoff points for a good airline ticket price?

Domestic airline ticket prices stay reasonable, on average, up to about 21 days before departure. At that 21 day mark, most airline seat prices will jump up. Exactly how much it will jump varies based on each itinerary. Just know that it very likely will.

International airline ticket prices sometimes require you to buy earlier to get the best deals. The best strategy is to shop early and often for your international tickets, and arm yourself with the latest CheapAir International When to Buy Study in order to see how airline ticket prices are trending.

The typical airfare changes 30+ times from the time it is published until your departure date. That’s why people tell stories of checking a fare before they go to lunch, and returning to find it’s gone. We can’t stress enough. In the airfare pricing game – there’s just no good reason to wait to buy if you see a “good price” online. Remember, if you see a good airfare, so do the tens or hundreds of other people searching for that same itinerary!

The 7-Day Rule and your airline ticket price

After that first guaranteed “bump” of your airfare price at 21-days out, you can expect to see another price increase at the 14-day mark, and then again at the 7-day mark. At each of these points, you can expect the prices to go up – exactly how much is hard to say.

The Hail Mary Zone for Purchasing Flights

Once you are inside of 7 days, all bets are completely off for you getting a “cheap” flight. The airlines count on business travelers to buy the last minute airfares at a premium, and business travel is back, baby! You can read all about the Booking Zones in our Annual Report, but this is not the place you want to be shopping unless it’s an absolute emergency. Prices will continue to rise this last week, and it gets ugly fast!

Final thoughts on the advance purchase timeline

Our conservative advice is always to buy in the sweet spot – which we like to call the “Prime Booking Window,” but which you’ll recognize as that place to buy an airline ticket that will be a “good deal.”

It’s super easy to overthink “when to buy,” but if you keep in mind that it’s almost never going to be within 21 days of your departure date, you should be in good shape.

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