Airfare pricing buckets & airline fare basis codes REVEALED!

In this post, I will shed some light on how airlines assign fare basis codes to the various “buckets†of inventory available for sale on any given flight. If you’ve ever wondered what pricing “buckets†are, or just what your fare showing as WAGT14GS means, read on. My recent Mileage Run 101 posts (Part 1 and Part 2) got me to thinking about demystifying these rather unfriendly looking codes, and I draw upon my experience working in Inventory Management (IM) at United Airlines, as well as my personal fascination with codes and logic in general, for this tutorial. The middle “Fare Class†column below, as shown using the FlyerTalk tool of FareCompare, is what I’m referring to [Edited to add: Since this post was published, FareCompare took down the FlyerTalk tool, sadly]:

a screenshot of a table

Image courtesy FareCompare

Since I’m most familiar with United’s fare basis structure, and some of the logic & sequencing hasn’t changed in decades for domestic fares, I’ll discuss those here. Keep in mind for now that other airlines have slight variations to their coding logic. To start, it’s important to first look at that leading letter of the “fare class.” The second line of the chart above shows a fare basis of GA14CS as the fare class for the $160 base price from Los Angeles to Nashville. G, then, is the “bucket†this fare falls into, a way the airlines categorize fares based on their yield potential. (That first fare to St. Thomas is out of scope for purely “domestic†fares, but I plan to decode international and other outliers in the future.)

There are presently almost two dozen revenue buckets at United, namely F & A (first class); J, C, D & Z (business class); and Y, B, E, M, U, H, Q, V, W, T, S, K, L & G (economy/coach class). Each represents a level of revenue contribution to the carrier, and all fare bases are not created equal. Basically meaning that you can’t arbitrarily assume the fare and/or yield of a ‘S’ fare, for example, carries the same weight across all routes.

Within each bucket, there exists a range of contribution levels depending on the origin & destination (O&D) of the ticket purchased. This simply means that a ‘S’ fare might generate a better yield to the airline if flown on a ticket purchased from Seattle to Chicago to Atlanta, versus a ‘S’ fare flown from just Chicago to Atlanta. Since the airline wants to maximize the higher earning buckets and overall yield, they may restrict S-class from being sold on that Chicago to Atlanta flight, but offer it on the Seattle to Chicago to Atlanta connection combination. For an excellent summary of this “married segment†concept, take a look at this current article by Ben Schlappig, an indefatigable mileage runner well beyond his years.

Now here’s where the airline yield management systems really come into play. Those systems, such as the one I worked with during my tenure in Inventory Management (IM) at United in the 1990s, optimize literally more than one hundred combinations of buckets across every O&D market to determine how many seats to allocate within each range and bucket. This process is constantly running in the background, but analysts in IM do go in to make adjustments, as I did for my assigned markets.

How to determine the amount of seats to authorize within each input area is highly proprietary, but the basics include using historical flight data, seasonality, market demand, and competitive considerations. So, the reason the lowest fares you’re searching for may already be sold out is because the airline thinks they’ll be able to sell those seats at a higher value & will assign them accordingly.

Okay, back to fare bases. Now that you know about buckets and why there are so many of them, let’s look again at the rest of the alphanumeric characters following that leading identifier. The second letter usually determines if it’s a one-way or roundtrip fare. Without exception, an ‘A’ domestic fare on United means it’s one-way, and an ‘E’ means roundtrip (excursion). Mileage runners like myself aim for those one-way fares since we know there aren’t any minimum stay requirements and can then turn right around and continue flying without a stopover. Using that L.A. to Nashville fare basis again (GA14CS), we know it’s a one-way fare since the second letter is an ‘A.’ Great, let’s move on.

Most of the time, the numbers contained within the sequence refer to the advance purchase requirement of the fare. Using the Nashville example again, GA14CS, the 14 here represents the advance purchase (AP) required to qualify for that fare. Pretty simple. However, there may be some other fare bases out there with more numbers.

For example, there was a fare out there yesterday from Los Angeles to Newark showing a fare basis of WEG143GS. We know it’s assigned to the W bucket, but what does the 143 mean? In this case by reading the fare rules (via ITA Software or ExpertFlyer), you’ll see the fare does have a 14-day AP, but also has a minimum stay requirement, generally requiring a three-night stay, hence the ‘3‘ attached directly to the end of ‘14.’ You can easily break out what might be the advance purchase by knowing the most frequent ones are 7, 14, and 21 days. I’ve also seen 0, 3 & 10-day APs out there, too, as of late.

The next letter in the Nashville fare (GA14CS), for example, is a C. Most of the time, but not always, it represents an internal pricing strategy the revenue management (RM) department wants to assign to the fare, and generally has no correlation to an element of the fare rule. But like I say, that’s not always the case, but I’ll come back to that after I shed some light on that last letter of ‘S.’

Also without exception and unchanged for years at United, if a ‘S’ or ‘N’ follows anywhere after the advance purchase & minimum stay numbers for a domestic fare, it means the fare is non-refundable. It is commonly the last character in the string, but may not be always, as in the case of the Los Angeles to Augusta fare of LA21N6K appearing in the list above. It’s my assumption that the –6K is also a unique RM identifier not correlating to a specific fare rule element.

So, we now know the GA14CS L.A. to Nashville fare is a one-way (‘A’), non refundable (‘S’) fare in the ‘G’ bucket requiring a 14-day advance purchase (14), while ignoring the ‘C‘ for our consumer-centric purposes. What about that WEG143GS fare from L.A. to Newark I mentioned above? We know it’s a roundtrip (‘E’), 14-day advance (14) fare with a minimum stay of 3 nights (3), is nonrefundable (‘S’) and the second ‘G’ is unimportant to us, but what about that first G?

Reading the fare rules, we know (via my IM experience) that ‘G‘ denotes the fare is valid only on nonstop flights. Sometimes United will use that same letter, or perhaps a two character combo, but I guarantee there is something specific in the fare rules that letter refers to. And it will always appear before the numeric portion of the fare basis. Another similar fare basis was out there yesterday from L.A. to New York (all airports) of WAG14GS. Again, this fare is valid on nonstop flights only as denoted by the G.

As you can see, there actually is logic to the rather cryptographic looking fare basis codes, and each airline has their own practice with which to assign codes. American has a totally different combo of letters and numbers, but with a little research into the rules, you’d be able to figure out a general sequencing as I’ve done above for United.

I actually have one more nuance to reveal. Assuming the fare stays live here for the next couple of days & the fare rules don’t change, I’m referring to the L.A. to Washington DC (all airports) fare basis of WAGT14GS with a base of $296. Anyone want to take a guess and decipher the ‘T’? Hint: The answer definitely lies within the fare rules, and it’s not simply a two character way of denoting the fare is valid on nonstops only. I’d enjoy it if one of my few readers commented with their answer, but if no one does, I’ll post the answer in a comment during the next couple of days.



  1. It looks likes the T means there are time restrictions. Looking at the LAX-IAD QAT21GN code:

    The codes missing the T do not seem to have time restrictions.

    Also, a question. How did you get that information to display on itasoftware? I looked for it on the old and new interfaces and can only get info on specific flights, not all fare classes available for a given airport. It would be useful to see all fare codes IAD-XXX to give me some ideas on creative bookings.

  2. Hi Tarpie,

    You’re absolutely correct. The ‘T‘ in the fare basis you used, and in my WAGT14GS example, do indeed refer to time restrictions as detailed in the fare rules. Nice job!

    And I’m very sorry… I mistakenly posted the fare listing chart as coming from ITA Software, when I should have attributed it to FareCompare. My apologies & I’ve corrected the post and link. Thanks for bringing that to my attention!

    The FareCompare list only goes so far, though, showing a limited amount of fares & fare bases from an airport you select. To see all fares in a market, I end up using ExpertFlyer.

  3. I won’t bore you with the whys and wherefores (right now anyway). However, can you tell me what this “fare basis” means: QUA14UPN? Thanks!

  4. @DH: It looks to me like the QUA14UPN fare is valid only on United-operated flights “UA,” requires a 14-day advance purchase “14,” grants an instant upgrade to first class “UP,” and is non-refundable “N.” Would love to know which market you found that in so I can read the detailed rules.

  5. Hi Darren. Here are some details. I purchased round trip first class tickets from AA (online) which included a SEA-SFO and SFO-SEA segment on UA. I couldn’t “see” the fare basis on the online AA reservations. However, my reservations were showing the first class cabin, i.e., “booking code A” on the AA online reservation that I printed out. I had to go to the UA web site to select my seats for the UA SEA-SFO-SEA segment (a different online locator code than the AA online locator code). My “United First” “A” seats were assigned and confirmed by UA online, and I printed that record out as well (bearing in mind that I couldn’t “see” the fare basis on the UA web site either). I had absolutely no trouble with UA in SEA, and flew first class to SFO last December. However, on my return the same month, my seats were given to somebody else, and I was put in the economy class cabin. I asked (in writing) for a refund (for the difference between first class and economy class seats) from UA, who referred me to AA by snail mail letter (which letter does not mention the fare basis, incidentally). I asked for a refund from AA, and AA “finally” just today (5 months later) quoted the QUA14UPN fare basis…and as a “gesture of goodwill” gave me a coupon for a couple of hundred bucks on my next flight. My concern is that in the future, I need to be able to “see” the fare basis BEFORE I purchase my tickets from AA (or any other airline). Anything that you might be able to “decode” here for me will be appreciated. Thanks!

    • @DH: It’s always a huge disservice when you’ve paid for something rightfully yours (the instant upgrade fare), and get reassigned to coach. Sorry to hear that, and it might have been to accommodate a Federal Air Marshall (FAM), or another operational reason. It happens sometimes, so here’s hoping that’ll be your “quota” of downgrades for the rest of your life.

      And yes, having been booked in ‘A’ on the United flights is indeed correct for the instant upgrade “UP” fares. United referred you back to American to settle the issue since they originally issued the ticket, although it was indeed United’s fault for downgrading you. Sorry you got a run around, but happy AA at least sent you a couple hundred.

      In the future, you might want to first build an itinerary using ITA Software’s Airfare Search tool. It will show the full detail, including rules & fare bases, for each segment of an itinerary. Then, head back over to AA or wherever you book & purchase tickets.

      Thanks for stopping by & please feel free to reach out if you have any other questions.

  6. Hi Darren. Well, here I am again. I’ve got the following fare basis on hold: FA2AA (American Airlines).
    Can I be downgraded/reassigned like I was with fare basis QUA14UPN (purchased through American Airlines for a leg on UA)? I’ve got 24 hours to make the purchase. The “fare rules” are so long and so detailed that I have little patience with them. I just want to go first class, and be assured that I’ll return the same way. Thanks!

    • Hi DH,

      SHORT ANSWER: No, you are holding a full-fare first class ticket and should not be downgraded.

      LONG ANSWER: So long as all of your travel is on AA for that fare basis, it is listed as a full-fare first class (none of the Q-UP stuff from last time), so the absolute only reason for a downgrade would be if a Federal Air Marshall (FAM) bumps you out of your seat “for operational reasons.” As I mentioned before, I think you’ve had your lifetime quota of downgrades. The only way to be 100% sure you won’t get FAM’d again is to pick a window seat. They ALWAYS have to be in an aisle seat for obvious reasons.

      I think you’ll be just fine this trip… happy travels!

  7. Hi Darren. I’m thinking of booking a trip online which AA says is first class (“A” booking code) inside CONUS and business class (“I” booking code) outside CONUS. It appears that the “A” and “I” legs of the trip going and coming are in fact operated by AA (i.e., not operated by other airlines as is sometimes the case, e.g., AA’s “OneWorld partners”). The fares going and coming are about HALF that of the advertised full first class/business class fares. My first question is this. Why is the CONUS travel “first class”, but the OCONUS travel “business class”? After all, it’s the same cabin isn’t it? My second question is this. Considering the fact that the fares are roughly HALF the advertised full fare—do you see any possible “surprises” with the departure fare basis (IRT50AP) or the return fare basis (IRT7HOL)? I’m pretty sure that the “50” in the departure fare basis means that I have to purchase the ticket 50 days out. Why there is a “7” instead of a “50” in the the return fare basis, I don’t know. Incidentally, the FA2AA fare basis on my last flight turned out to be “as advertised”, i.e., the first class cabin. Thanks again for your advice on that one!

    • Hi DH, glad your latest FA2AA flights went well. For the A vs. I situation, American markets the first class cabin on 2-cabin aircraft as business class for points outside the “normal” U.S. destinations, such as the case of Miami to San Juan or Miami to Lima, Peru. You’re correct re: the 50 on the outbound fare basis. Most discounted business class fares require a 45-day to 50-day advance purchase. You must be traveling around the holidays on the return, which is what I’m going to assume the HOL means. The only concern on these fares is the ability to change your ticket. If you changed the outbound, you would still need the advance of 50 days or else they’d make you buy up to full fare business. On the return, you “may” be safe with changes 7 days or more from departure, but be forewarned Holiday fares carry incredibly restrictive date ranges. Also, I said “may” because I’ve known of some discounted business class fares that deem the most restrictive rules on any fare basis apply to the total ticket. Otherwise, yes, these are totally valid business class fares with the only risk of downgrade to be if you were FAM’d or an equipment swap took place to an aircraft with fewer seats. Happy travels! (P.S. You’re quickly becoming an expert with fare bases!)

  8. Hi Darren. Thanks for reviewing the fare bases for me! I have one final question if you don’t mind. Is it usual these days for an airline (AA in this case while booking online) to not allow a seat selection for the following:
    1. Foreign flag air carrier legs of an overseas trip.
    2. AA leg inside CONUS upon return to the U.S. from oveseas.
    If this is outside your area of expertise, I’ll certainly understand.

    • Hi DH, I’ve been in your situation #1 and have called the operating carrier to secure my seats, so yes, as far as I know you cannot pre-assign seats online or otherwise on an American booking with a different carrier. Your #2, however, I have no experience with. I’m surprised you can’t assign an AA seat on an AA reservation within the contiguous USA.That baffles me completely. Hope your travels are fantastic!

  9. Hi Darren. The answer I got from AA was to call them, so they could “troubleshoot” my issues verbally (rather than in writing). In any event, Darren, you’ve gone “above and beyond” as to my inquiries. Thanks very, very much! P.S. I’d turn back the clock to the pre-deregulation era of air travel if I could…back when traveling economy class was not like being stuffed into a sardine can.:)

  10. Hi Darren! Wow! You really know your stuff! Please, can you help me?! My fare basis says: SZX7UT. Huh?? Also, do you know what 1-6/NO CHG/NONREF/ZA means under “endorsements/restrictions”. Thank you!! -Kat

    • Hi Kat,
      Which carrier are you flying with the SZX7UT? The other stuff means you have a nonrefundable ticket which allows no changes. You’re on a “S” bucket ticket that was probably a 7-day advance purchase fare (though you probably bought it much earlier than that). The ‘X’ on United usually means travel on Monday through Wednesday, but again… it depends on which carrier you’re flying. Sounds like an “off-peak” fare to me. That definitely doesn’t look like a United or American fare. Southwest? Another carrier?

      • Oh, sorry, forgot to say! It’s Japan Airlines, codeshare with AA. And I’m traveling on a Tuesday. And I bought it near 30 days in advance. Basically, I wanted to know if it was non-refundable and if the dates could be changed. But you said no above, which answered that for me. Thank you so much for your response, I was searching all over the web for these codes-decoded to no avail! Thank you!!

  11. Oh…uh… Fare difference? So if if this flight costs (for ex.) $1000, and I change it to a day that costs $1500… My cost of changing flights would now be an extra $750?

    • You’re correct… especially if it’s the outbound flight you’re looking to change. They’ll refare the whole itinerary and you’ll be responsible for the change fee AND any fare difference. If travel has started and you’re changing the return to another flight within the same fare rules and the “S” bucket is available, you will likely only have to pay the change fee.

  12. VLXEBNE1 from US Airways. What does it mean? We are trying to fly from Phoenix to Brussels. Thanks for the great work

    • @GennyfromtheBlock: It looks like that’s an active fare basis code and I looked up the info on ExpertFlyer. V, of course, is the bucket or booking class. The L represents a particular date range for the fare and is off-peak (not summer travel), X means travel to BRU on a Sunday through Thursday, back on Monday through Thursday, and I honestly don’t know what the BNE1 refers to. Probably a combo of non-refundable and some other US Airways-specific identifiers.

    • @DBF: Good guess, but no. The “T” actually refers to time restrictions. In this QAT21GN example, the “T” ended up referring to flights between 7:30am – 12:30pm and others specific to that fare. It’s long gone by now, so I don’t have the specifics, though Tarpie’s comment (the first in this post) has the actual language. Still though… good guess!

  13. Hi, thanks for your interesting article. If you know the booking codes from ITA can you quote these on the phone when booking with the airline? Cheers.

    • @Andrew: Thanks! And yes, you could indeed mention to the agent the codes you found on ITA, although they might think you’re weird for knowing them. 🙂

  14. Awesome and interesting article, Darren.

    I am flying with UA with fare code SAXSC listed (company booked the ticket). I have no idea what it says, but it is economy and cheap, that much I know. 🙂

  15. Can you explain this United issue about fare classes? thanks so much

    on the Mileage Plus Statements
    they list the fare class in a format xx/xx

    actual examples:
    6/23/2012 United 117 ZZ/ZZ
    7/17/2012 United 116 ZH/ZH

    Both of these were economy tickets, with upgrade to business with mileage and co-pay. Are these both considered discount business fare? On the ZZ fare I get full 1.5 premier miles, but on the ZH not.

    In the past, when ever this happened, I would contact them and they would give me the 1.5 times premier miles. The 1.5 is for platinum status and business class.

    Which is correct? Is ZZ and ZH both discount business, or is it like ZH business that does not qualify for the Mileage Plus benefits??

    In my case it is significant. Over a year for me I lose about 32,000 regular miles AND 32,000 premier qualifying miles.

    • @chad: The preceding ‘Z’ simply means you were upgraded. The second letter generally refers to the fare bucket/class you purchased and is the basis for mileage- and premier-qualifying-mileage accrual. Upgrades using mileage/co-pay (and others, such as complimentary and those supported by an instrument) do not qualify for 1.5 miles/segments. You say the 6/23/12 flight was a purchased economy ticket? If so, I’d consider yourself lucky that you got the ZZ 1.5x bonus. That’s likely an error (which happened to me early in the year when their systems weren’t posting miles correctly). Otherwise, upgrades from economy never get 1.5 miles. If you purchased a fare basis/bucket of ‘Z,’ however, it is discount business class and does accrue 1.5 miles.

  16. Thanks for your help! All United needed to do was tell me the info? So the second letter is the fare class. That is the missing link.

    I think, the ZZ ones I have were purchased upgrades, NOT with miles. So they qualify for bonus.

    While I have ZH and ZS those are mileage based upgrades with copay and therefore not qualified for bonus.

  17. Great write-up! I already knew about the fare classes and number of seats and all that. However, I’m curious about something. Yesterday I saw a flight that had 9 S-seats available. I figured I’d hold off for a day before asking the boss if I could take those days off. This morning that flight only has 1 S-seat left. So apparently 8 people bought a ticket overnight for a flight that’s three months out…well, OK. But do you ever see that more seats get allocated to, in this case the S fare down the road? Or should I suck it up and go with the W fare before that also fills up? (Traveling with two family members). Thanks in advance!

    • @Nico: Thanks! 9 is the maximum number of seats viewable in each fare bucket, though more are usually for sale. And those allocations are constantly adjusted by both the system and human intervention. So the S-bucket might be repopulated for your flights (or might not). It’s a guessing game. And I’d base my decision on whether to purchase or not more on the fare value itself, not paying so close attention to the buckets. As they say, “fares can change at any time.” If your planned flights are three months out, maybe watch a couple of more days before pulling the purchase trigger.

  18. @Darren: Thanks very much, Darren! It was probably more of an academic question as you’re right – I don’t want to chance it and get stuck with higher prices since the fares themselves are subject to change. Thanks again!

  19. Pretty good explanation, I have came to know some of these fare bases now.
    There is a fare I booked: EABU/QREU on China Southern, which seemed a cheap one so went for it in Economy. Please confirm if I understand correctly-
    E and Q is the fare class for outbound and inbound, A stands for one way, R would be for return (?), but the rest still am oblivious about. Would appreciate your inputs. Thank you!

    • @Kumar: I’m unfamiliar with China Southern’s fare basis logic, as there’s (generally) no universal standard for the letters after the leading digit (which as you note is the fare class/bucket).

  20. @Darren, I was able to get the other fare classes from the airline today, the main Trans-pacific legs are in E and Q that’s why these showed up as such while the connecting legs are in M class.
    A very good post to get such information for some one like me. Thank you again!

  21. Hi Darren

    Thanks for all the useful info.
    Do you know about transatlantic airfares (code basis)?.
    I bought a ticket from San Diego through Newark and onto Dublin on a cheapo ($1330) ticket. Now I’ve discovered I have basel cell carcinoma and I need surgury and I won’t make it. I’m booked in fare basis
    “S” I know it was really dumb to book a flight in this fare basis, but, I didn’t think I was going to get diagnosed with Basal Cell Carcinoma with a tumor that I need to get cut out of the back of my neck and recovery time (got it in time, it’s curable).

    My dillema is that I’m not sure of the dates that I’ll be flying now. I can upgrade to a higher fare basis, but, there doesn’t seem to be a flexible fare basis (without paying $300 if I change the date) even if I do upgrade.

    I called United and got a customer service person from Spain (lived there a year many years ago) still strain to understand their accent. I asked to be put onto a supervisor who was also Spanish, very evasive about fare basis and essentially told me that no matter what fare I bough (unless I paid 3 or 4K) there would be a $200 to $300 dollar change fee each time.

    Sigh! So difficult trying to get an honest answer out of United customer service staff that are outsourced these days!

    • @Maria: I’m so sorry to hear about your surgery (but happy it was caught in time!) And no…. you weren’t “stupid” to book S-class… $1,300 isn’t cheap (at least to me). But it is, sadly, one of the coach fare buckets that carries restrictions, as you’ve found out. It will indeed cost $250-$300 (depending on when you bought the ticket originally) to apply the value of your original fare to a new ticket. I’m in a similar situation as I had to cancel an international reservation on United earlier this year. Just note, you have to use your original ticket within a year of when it was issued.

  22. Does anyone know when a K class might be available 7 months from now on a United flight? Are they late additions based on availability? thanks..

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