Something odd has been happening when I am trying to book a one way ticket in First/Business between FLL and SAN in early December. When booking the two components of the fare FLL-CLT-SAN - the fare is shown as Ł398. So far, so good. It is booking into I class. When I put my details and that of my husband - it comes back saying "Please change the search as one or more of your flights is no longer available". I have tried different flights, and indeed changed browser to see if that had anything to do with this result. When I go back to the flights it still shows as Ł398 and the result is the same. Is this a glitch or am I doing something wrong. Any help would be appreciated!

I tried your itinerary for early December and it went through without issue. Are you searching FLL-SAN or doing it by segment?

Thank you! By segment - I wanted the 14.45 to FLL - CLT and the 18.05 CLT - SAN. When selecting it gives me Ł398 - when I try to go to buy or hold it gives me the No Longer Available message.

That sounds like married segment logic. The class availability for two segments individually is not necessarily the same as it would be when they are put together. And AA.com will put them together even if you try and do it individually.

That makes sense - what you say I mean not the workings of AA.com. Why it should be different I cannot understand, but it sounds like the possible reason. Thank you!

Almost certainly married segment logic. The flights individually may have I fare bucket availability when purchasing flights separately on each segment. However, there is separate seat inventory when purchasing the segments together on a single fare (this is the married segment inventory), and there can frequently be no I fare bucket inventory open on the married segments even when it's open on the individual flights. Unfortunately, when you search hop-by-hop using multi-city, the fare search engine is only looking at the individual flight bucket inventory and will quote through fares based on that. It's not until you go to purchase where it does a check on the actual married segment inventory for the fare and can discover that it does not match what's available on the individual flights. The message is misleading because the fare was not actually available at all on these particular flights. It's just that the fare search engine did not discover that fact until the final checkout phase when it actually checked the married segment inventory.

I've definitely experienced this on simple round trip searches as well.