Why do airfares change so much? CheapAir.com has been called every name in the book by customers who do a flight search, see a fare, and come back later to find that the fare has gone up by $50 or $100. “This is bait and switch!” they say. And it’s hard to blame them for being frustrated.

Yet, we also get e-mails that heap lavish praise on us after we contact a customer to tell them that between when they paid for their flight and we went to process it, the fare went down by $25 or $125.

The reality is we don’t deserve the criticism or the credit.  It’s the airlines who set the prices—we just seek out and present the best ones.  And as many of you have noticed, airlines change fares often.

So, why is that? Why do airfares change so much? Why is checking a fare like playing the stock market – up one day, down the next, with seemingly no rhyme or reason?  Here’s a little lesson on airfare pricing that will attempt to give you a better understanding of what’s going on behind the scenes as you shop for fares.

Why Do Airfares Change: The Airlines’ Pricing Dilemma

The airlines want to be able to have their cake and eat it, too, and they go to great lengths to make that possible.  They employ a very high-tech strategy called yield management which intentionally aims to charge different prices to different passengers in order to maximize the total revenue collected for each departing flight.

Here’s what we mean: Let’s say you’re an airline.  You have a plane with 100 seats on it that you’re going to fly from Point A to Point B.  There will be a group of people — business travelers, travelers with family emergencies, people who just don’t care about the price — that are willing to pay a ton of money for a seat on that plane. We’ll call this the “go-at-any-price” group.  Additionally, there will be a much larger group consisting of price conscious individuals who would love to travel but don’t necessarily need to. This second group may be willing to buy a ticket on this flight, but only if the price is affordable.  We’ll call this the “go-if-the-price-is-right” group.

Air Fares 101 - Why do airfares change all the time?

The Airlines Want Flights To Be As Full As Possible

The airline’s dilemma is that if they set the price per seat at the maximum price they can get from the “go-at-any-price” group, they would generate a lot of revenue from those passengers but they would be flying planes with a lot of empty seats (a wasted opportunity for even more revenue).  On the other hand, if they fill the plane by charging fares low enough to attract all the “go-if-the-price-is-right” travelers, they will be giving seats to the “go-at-any-price” crowd for far less than they would have been willing to pay.  The thought of that makes the airlines cringe.

An airline’s goal is to get as much as they possibly can for each seat on the plane.  If 10 people are willing to pay $1000, they would love to sell 10 of the 100 seats for that price; if there are another 20 people willing to pay $500, then they’d sell 20 more seats at the $500 rate; and so on until the plane is full.

But how can they do that?

Same Seat, Different Fares

Airlines never just have one fare – they have several, even dozens, of fares for each seat and they employ sophisticated techniques to maximize the number of people who get stuck paying the higher of those fares.

Here’s a real-life example.  United Airlines currently publishes 43 different one way economy class fares for flights between Los Angeles and Chicago.  These fares start at $109 one way, but there are also fares of $139, $149, $159, $189, etc. all the way up to $1765!  The highest fare is more than 16 times more expensive than the lowest fare even though, no matter which price you pay, you’ll end up with the exact same seat, the exact same food (or lack thereof), and the exact same service.  (To be the fair, the very highest fares do usually include a few extra, but relatively minimal, perks like being refundable, easier/cheaper to change, first dibs at the best seats on the plane, etc. but nothing that substantially changes what you get for the fare that you pay.)

Why You Purchase the Highest Fare More Often

Knowing that a given seat on a United Airlines flight to Chicago may cost anywhere from $109 to $1765, you would naturally say “I’ll take the $109 option” but, of course, the airlines don’t make it that easy.  Their goal is to funnel every would-be traveler into the highest “fare bucket” that they can.  They do that, first, by adding restrictions to the lowest fares that limit how many people can take advantage of them.  For example, the $109 fare to Chicago requires you to purchase it 21 days in advance and to fly on Tuesdays, Wednesdays, and Saturdays (the least popular travel days, where it’s harder to sell seats at higher fares).

Other fares have 14 day advance purchase requirements and, still others, 7 day.  Some fares are blacked out around holiday and other peak travel times.  Generally speaking, the lower the fare, the more restrictions there will be on it, and the fewer flights that that fare will be offered on. This is also why airfares change.

Air Fares 101 - Why do airfares change all the time?

Availability: The Number of Seats Available at a Particular Price Determines What You Pay

But just as important is the fact that, even if a fare is offered on a certain flight, the airlines will limit the number of seats available at that fare level.  For example, United may say that on a given flight they will only sell up to 10 seats at the $109 fare, 15 seats at the $139 fare, 20 seats at the $149 rate, etc.  From a practical standpoint, this is the probably the most important point to understand about airline pricing.  As more seats are booked on a flight, more fare levels will be “closed out.” The end result is that additional passengers will be stuck paying higher fares.

It’s actually even more complicated in practice.  Airlines actually have computer programs that are constantly monitoring flights, analyzing booking patterns, and in real-time changing the number of seats available at each fare level.  If a flight is booking up faster than expected, an airline may decrease the number of seats available at some of their lowest fare levels, or wipe them all out altogether.  If a flight is not selling well, suddenly more seats may appear at fare levels that were previously “sold out”.

Why Fares Change all the Time

If you see a different fare today than you saw yesterday, it’s likely that seats in the lowest fare categories sold out or were closed out.  For instance, if there are 3 $109 seats left on our example flight to Chicago and someone grabs them, the lowest fare available will change to $139.

If United’s yield management system looks at the flight and says “Wow, bookings are strong”, it may choose to close the $139 level, too.  Then the fare will appear to “jump” to $149.  But what if two days later 2 families of 4 booked on the flight decide to cancel?  The same system might say “Uh-oh, we have way too many empty seats” and decide to open the $109 and $139 fare levels back up.  This process happens continuously until hours before departure.

Explaining Airfare Volatility

Over time, fares on a particular flight will get higher as more and more seats gets booked and more fare levels close.   But there are short term blips all the time. So, if you look at it hour to hour or day to day, there will be moments when fares temporarily dip before heading back up once new bookings come in.  This entire process is extremely dynamic. At any given time there are hundreds of thousands of shoppers looking for flights and making reservations. And of these, each reservation may have repercussions on the fares paid by subsequent travelers on the same flights.

Air Fares 101 - Why do airfares change all the time?

Airline Fare Sales

What about fare sales?  Airlines are constantly promoting one sale or another, after all.

The real news would be if there were no sales going on.  To the airlines, almost everything is a “sale”.  Returning to our United Airlines Los Angeles to Chicago example, of those 43 fares, about two thirds of them are considered to be “sale” fares.  A “sale” fare really just means that it requires booking or traveling between a specified time period.  Some sale fares are really good deals. Others are worthwhile because they provide decent fares on dates or times that previously weren’t eligible for the lowest fares. Still others are just plain meaningless. They are no better than one or more other fares already in the market.

Remember this about so-called sale fares. A fare that is really lower than the other fares in the market will be even more limited from an inventory standpoint.  For example, if United introduces a 3 day sale fare to Chicago for $99, it will almost definitely not be offered on flights where the existing $109 fare has already been sold out.  In practical terms, this means that when sales hit the market, they will usually only be obtainable on flights that are pretty wide open.

So – once more – Why Do Airfares Fluctuate All the Time?

The bottom line is this:

– It is not uncommon for fares on a particular flight to change on a daily, sometimes even hourly, basis
– If you see a fare, know that it may not be there the next time you search. It could be higher, it could be lower
– Neither CheapAir.com, nor any other on-line travel agency, has the ability to set prices. We do a really good job and sort through tens of thousands of options to find the best deals. However, it is the airlines and their pricing teams who are actually responsible for those deals
– Fares on a particular flight will generally increase as the flight becomes more heavily booked. But at certain points, fares may fall dramatically. This can happen if a fare sale is launched. Algorithms can also determine booking levels are below where they should be for a given departure date

The Top 5 Tips to Keep Your Flights Affordable:

1. Start your search early.

The best way to get a good fare is to book early. This helps increase your odds of getting one of the lower fares.

2, Consider alternative airports.

This can be a worthwhile alternative if you’re near a larger airport. Sometimes the savings can justify the longer drive if your payoff is to catch a more reasonably-priced flight.

3. Book your flights in the “Prime Booking Window” to get better-priced airline tickets.

CheapAir’s The Best Time to Buy Flights offers a simple breakdown to help you buy flights. Use our when to buy booking tool to help you find the best-priced flight. Learn more about why the “Prime Booking Window” is the best time to buy cheap flights.

4, Consider managing upfront costs with monthly payments.

Monthly payments can help travelers defer up-front travel costs and pay over time.

5. Protect your purchase with Price Drop Payback in case airfares change.

Finally, CheapAir.com also protects your airfare with our free Price Drop Payback program. We’ll give you back up to $100 a ticket, should your fare go down after you purchase.

Now you have the answer to that eternal travel question – why do airfares change so much. Knowledge is power. We hope you use it and have a fabulous vacation. Have a question about why airfares fluctuate so often? Ask us in the comments below.

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  1. Demystifying airfares: Why do they change so often? This article tackles a common question with clarity and depth, shedding light on the factors that influence airfare fluctuations. With practical examples and explanations, it’s an enlightening read for travelers seeking to understand the dynamics of pricing in the airline industry. Thanks for the valuable insights!

  2. Curious about this:
    Would airlines lose money if they figured a fixed price for All seats on a flight (priced accordingly for class), regardless how far out it was purchased, that would ensure the highest number of consistently full flights vs all the money spent analyzing and trying to figure out how to manipulate people in to paying the most possible?

  3. Curious about this:
    Would airlines lose money if they figured a fixed price for All seats on a flight (priced accordingly for class), regardless how far out it was purchased, that would ensure the highest number of consistently full flights vs all the money spent analyzing and trying to figure out how to manipulate people in to paying the most possible?

  4. We have used CheapAir 4 times thus far. Each time has been a great experience. Things I like; They are US based!! When I call, I get a REAL person, and I do not have to press 1 for ENGLISH blah blah blah. It is especially fun for me when I get someone I have talked to in the past, and we remember each other!! (Hi, Danish!!!)
    Last year, in October, the airline (American) CANCELLED our flight. I just happened to call Cheap Air to make sure we were still a go. (No). WHAAAT?!?!?!? Does the airline just out-of-the-blue do this on a regular basis??? (yes) GAAAAHHHHHHHHHHHHH!!! The Cheap Air Tech I was talking to let me know (after I got done having a panic attack) that there was room on a flight leaving a day earlier. COOL!!! This little snafu worked in our favor, in a way. Our airfare was the same price, same flight time, and the only down side was paying for another day each hotel and car rental fares. I can live with that, because I over budget for our trips.
    Do I recommend Cheap Air? Absolutely!!!

    • So glad to hear that your experiences with us have been positive Jonette. We love to get feedback from customers and are thrilled that you’ve been happy with the quality of our support. I’ll make sure to pass these kind words along to our sales agents. They’ll be grateful you took the time to post such positive feedback.

  5. I’m still confuzzled lol back in June, flight prices for Emirates/Qantas were really low for Glasgow-Cairns via Dubai for 3 weeks and the prices were way under £1000, now they have frog leaped up to an eye watering £1500 and we’re praying god that by time we’ve saved in January (max we can afford is maybe £1100) the prices will be down a bit in the sales ???

  6. Well of course now it would not show now, it has been over two days. When I sent the messages it was still showing up until I would try and book. I even tried the next morning and then called, and was told that it takes a while to update the site (over 2 days?).

    You have probably not seen that low of fare, because obviously it wasn’t bookable, but it was shown on the site. I am sending the screenshot that is showing up on skyscanner right now. It is the same flight but on 1/4/18 instead.

  7. so I found a fare from SFO to ICN, RT so will have to see if I can add ICN to CJU reasonably. But while searching, found even cheaper FAT (home) to ICN but 30/36hr flights vs nonstop/20hr. But it makes a 22hr layover after FAT in SFO, even though the one I bought would fit in there for times. Why can’t I juggle the FAT-SFO to match with SFO-ICN and come out without the long layovers…if I change the date by a day, it still pushes SFO-ICN flight a day later 22-26+hr layover. If flight legs are open, why don’t they put them together to make shorter flights if available? Or would that make remaining trips end up with 48 hr layovers eventually?

    • Hi Dee, Can you send a screen shot to me at [email protected] of the $250 fare? I see $646 but I cannot find $250 anywhere. To be honest, I have never seen a fare so low from Los Angeles to anywhere in Asia. I’d like to look into this for you.

  8. Ok, just did another check for leaving 12/30 LAX to CJU, OW your site had a $250 fare, clicked it within 5 seconds…preparing itinerary…$646!!! So I refreshed the page and still has the $250 fare, until I select it. What gives there?

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