I've been trying to purchase this ticket

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for a week or so (from the AA website), but I kept getting the following message:

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Choose a different flight or fare. We're sorry but at least one of the flights or fares you chose is no longer available.

If you proceed to the available options, you can see that the very same itinerary is available for the very same price. But the AA website keeps asking to choose a different flight. I've tried modifying this itinerary a bit (moving it a few days back and forth), but it didn't help. Also, you cannot buy this ticket from aggregator websites, as far as I can tell (they all redirect you to the AA website).

I was wondering if this is just a technical bug or AA does not allow to purchase this itinerary intentionally (since if you look for one-way trips YVR-SAN by American Airlines, you will find that they are roughly twice as expensive as the route I'm referring to).

  • 4
    You're trying to circumvent their fare system by booking what's clearly a one-way trip with a layover, as two legs of a multi-city. So I'm not surprised that they won't allow it. The exact reason probably comes down to technical details of the fare rules, relating to the very short time between the flights (making it obvious that you have no interest in actually going to Dallas). Oct 21, 2019 at 21:51
  • 2
    Why not book it as two one-ways instead?
    – JonathanReez
    Oct 21, 2019 at 21:57
  • 3
    Just curious what's so great about this itinerary? A quick Kayak search shows UA has YVR-SFO-SAN for $162, which is cheaper and quicker and much less of a detour. Oct 21, 2019 at 22:07
  • 7
    @NateEldredge I'm not very familiar with that rule, but what if I need to meet someone in DFW (who also flies to DFW and with whom we agreed to meet on the airside of DFW) before going to SAN? Wouldn't such a scenario be a justification for purchasing the multi-city itinerary? If I purchase a one-way with a layover in DFW, then strictly speaking it need not be the case that the layover will indeed be in DFW; the airline's responsibility is to get me to SAN. By if I buy a multi-city, the airline's obligation is to get me to DFW first, and then to SAN, as far as I understand.
    – user557
    Oct 21, 2019 at 22:43
  • 1
    @NateEldredge This is not in any way back-to-back. The term you're probably thinking of is end-on-end, but it's not that either.
    – Doc
    Oct 21, 2019 at 23:40

1 Answer 1


You are being hit by one of the great joys of the airline industry known as 'Married Segment'.

Most airlines price flights based on the origin and destination of the travel, not based on the individual flights. ie, in this case they are charging you as if you were flying from YVR to SAN, regardless of the fact you're actually flying via DFW.

The "base fare" (before taxes/etc) that you're being quoted on this flight is what's called a "through-fare" so covers both legs of the flight - YVR to DFW and DFW to SAN :

(Output from matrix.itasoftware.com) :

Fare 1: Carrier AA VVACZSN1 YVR to SAN (rules)      $154.92
Passenger type ADT, one-way fare, booking code V
Covers YVR-DFW (Economy), DFW-SAN (Economy)    

Note the 'booking code V' in the text above - this is what's called a fare 'bucket', and is how airlines limit the number of "cheap" seats that are available on each flight. There will be a number of seats available for sale in each fare bucket, and as those sell out prices will go up as you move to the next fare bucket. Fare buckets were historically done on the basis of an individual flight, so YVR-DFW would have it's available seats, and DFW-SAN would have it's available seats. In order to get a cheap fare all the way through, you'd have to have availability on both flights.

Now, mixing the two concepts above (origin to destination fares, and fare buckets) can cause a problem for the airline. Maybe they want to sell cheap flights from YVR-SAN (perhaps because a competitor has a sale on that route), but they don't want to offer cheap seats from YVR-DFW or DFW-SAN as there's no competition on those routes so they know they can charge a much higher price.

Thus was born the concept of "Married Segments", which is where bucket availability can be done on a pair of flights. Thus an the airline might set the number of cheap seats available on YVR-DFW and/or DFW-SAN to be zero, but at the same time have a non-zero number of cheap seats on the combined YVR-DFW-SAN flight combination.

Now with that as background, what you're actually hitting here is the opposite of what I described above! Individually, both VVR-DFW and DFW-SAN have availability in the "V" fare class for those flights. The flight booking engine is seeing this, and is giving you a price based on that availability.

However the "married segment" of YVR-DFW-SAN does NOT have availability in V class - the lowest class it has availability in is the higher "K" class. When the system gets to the point of validating the fare is valid it's realizing that there is no sufficient availability on this married segment flight, and is bumping your ticket up to a higher K fare, with a much more expensive base fare :

Fare 1: Carrier AA K0ACZNN1 YVR to SAN (rules)      $312.89
Passenger type ADT, one-way fare, booking code K
Covers YVR-DFW (Economy), DFW-SAN (Economy)

Technically, this is a case of "working as expected", with the possible exception that Google Flights and the AA website should not have even offered you the cheaper price to start with for that combination of flights. You could try calling the airline and asking them to give you the lower price, but I wouldn't not be surprised if they refuse on the grounds of "no availability" of that fare on that combination of flights.

  • 1
    Your explanation implies that it should be possible to book them separately (with the usual consequences of no luggage transfer and delays are your problem) right?
    – Aganju
    Oct 22, 2019 at 14:22
  • 3
    Booking them separately would change the price as you'd be paying for YVR-DFW ($197 base fare in V) + DFW-SAN ($186 base fare in V), which works out more expensive
    – Doc
    Oct 22, 2019 at 14:45
  • @Doc so I guess that means the booking code V indeed has availability if booked separately but the cost for separate V bookings is higher than for a married V booking? (I guess as you said you are paying higher taxes for both routes when paying for them individually than the cheaper taxes of "straight line even though it has a transit point" YVR-SAN)
    – kiradotee
    Oct 22, 2019 at 14:57
  • Oh my god matrix.itasoftware.com is awesome, it's like Google flights but without all the mumbo jumbo and it has really clear UI - that's so awesome thank you. Oct 22, 2019 at 19:45
  • 1
    @BenjaminGruenbaum ITA software was acquired by google several years ago and is the behind the scenes back end for google flights
    – Aaron
    Oct 22, 2019 at 20:17

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