Here’s an interesting scenario where I believe the BA carrier-imposed fees make absolutely no common sense when converting from a AA codeshare to a BA prime flight on a ticket associated with an instant upgrade.

I originally booked JFK-LHR-DUB in economy given how cheap the fare was. The SWU to J was looking dicey so I took the very competitive instant upgrade to J and confirmed into F with the SWU. When applying the SWU to the BA leg (U space was open), I was told that there would be ~$1k in BA taxes (carrier-imposed surcharges) due. I had this confirmed twice.

My theory is that because I took the instant upgrade to J, my underlying fare remained in economy without the various surcharges in place on premium tickets within the JV / the instant upgrade doesn’t collect those surcharges. The switch to BA prime was forcing a collection of those fees.

Have those that applied a Y->J SWU on an AA TATL segment run into something similar when trying to clear the short-haul segment?

I’ve cleared a TLV/LCA - LHR and don’t remember paying any additional surcharges, even when having it booked on AA flight numbers.

Just to confirm was this AA JFK-LHR connecting to BA LHR-DUB? Or all BA JFK-LHR-DUB?

I have never upgraded a BA longhaul flight with SWU's, but I have upgraded many BA shorthaul flights connecting to/from AA at LHR (probably 10+ times since 2023 when this benefit started). Never once have they tried to charge any additional surcharge $$ for a shorthaul SWU upgrade on BA.

The TATL is on AA. If I had flown BA in W, I would have expected the BA surcharges to apply the SWU that others have experienced. I think it has to do with how the instant upgrade is processed in that you’re just paying for the seat with no change in the underlying fare basis.

For sure they can still see your original fare basis, but IMO that shouldn't have anything to do with it. Unless something has seriously changed recently, flying AA to/from LHR connecting with BA shorthaul you have never had to pay any additional surcharges.

My hunch is many if these rate desk agents are just clueless or as equally in the dark as we are with this process, especially with the correct way to calculate any surcharge add/collects and when it should be applied.

Economy JFK-LHR-DUB has ~$100 in YQ while business has ~$1000. So it seemed the agent was trying to collect the full YQ difference even though that difference should not be applied since the majority is tied to the AA metal longhaul portion.

In comparison for a standalone BA LHR-DUB flight the difference in YQ between Y-J is about $6.

Exactly. I confirmed that as well when looking at the ITA matrix fare breakdown compare. I may try calling versus chat / email, but given that it is an hour long flight, the exit row will do just fine, especially with no hot breakfast in CE

Oh dear, if this was over chat then yea I would definitely call.

100% To be fair to the chat agent, I was transferred so they were not the typical front-line agent that quotes you a set of flights totally different from what you requested.

The X team was helpful in confirming this morning that this surcharge was in fact accurate and there is no way around it when converting to a prime flight (no way to break out the short haul from long haul). They confirmed that it was not due to the instant upgrade.

I honestly think a big part of this is the opaqueness of how SWUs work on BA in terms of the fees as it seems like it has been all over the map based on this thread. I’ve only used them to go from J to F on BA where those surcharges are already the same.

For sure, that's sort of what I was getting at above, even the rate desk agents that process these upgrades seem to have no clear set process or rules and just go with whatever they think or with what little training they've had; Sometimes they try to charge the YQ increase for the whole journey, sometimes just the upgraded segment, sometimes nothing at all, etc. etc. Complete crapshoot.

And I wouldn't even trust the X team in this instance as converting the BA shorthaul flight to the BA prime flight number has never mattered. Going back to 2022 they have always had to convert the BA segment to the BA prime flight number to apply a SWU on BA, and this is the first instance I've seen where they're trying to charge any surcharge for a shorthaul upgrade (not to mention the entire $1k YQ amount which is ludicrous).

Basically either no one at AA knows what they're talking about but are trying to act authoritative on the subject, or this is something very new that makes SWU upgrades on BA completely worthless.

I'd try just calling and not mentioning anything about any of these exchanges, tell them you have an upcoming trip where you already applied a SWU but it looks like now space is open on the BA connecting flight and ask them to upgrade that segment too. See what they say, fingers crossed.

For me and LHR-western Europe tickets, I've had AA try to collect surcharges about 30% of the time (ranging from $0.14 to $26 / segment and ticket) and 70% no. On the 30% when they've collected it, about half the time they have not at first, only to for AA to either call me back a few hours to a day later and ask for it, or for the reissue to not go through until I call, ask why, and then pay. (When they don't initially ask for it, usually that's been less $5 / ticket).

(There is a separate category of issue where they try to collect the UK APD despite just connecting, regardless of whose metal.)

I completely agree on there not being consistency to this.

Called in a little while ago walking back from work and came up with the same result. The rates desk came back to the agent with the full YQ surcharge. I pushed back saying that the math should be in the $20-$30 zone as that includes the $1k on the TATL segment (it is very clear on the ITA matrix breakout). The agent went back and said that the rates desk confirmed that it is indeed just for the short segment / nothing can be done about it. Oh well!

I am convinced that it has to do with how the instant upgrade gets re-ticketed versus how a Y-J SWU on the AA segment gets re-ticketed. I feel like I am pretty good at navigating AA nuances, but this is one that has me stumped.

Definitely stumped. If this is a new "thing" then I have no idea what they're thinking as who in their right mind is going to pay $1k to upgrade a BA shorthaul flight, it makes no sense.

I have a waitlisted AA-BA connection in a few weeks so let's see what happens...

I would say that this is definitely the case. If you did an instant upgrade on AA, I would doubt very much that anything was applied towards carrier surcharge conponent paid and so when rebooking on the BA flight, the difference between YQ paid and YQ for journey undertaken would be applied

Given that this is just an intra Europe flight, there is little difference between economy and business - you already have lounge access and may well be more comfortable in an exit row seat in economy than a regular seat in business

This has been my experience as well. in the care of ryanbriar , I can imagine the Y-->J-->F causing an already incompetent process to absolutely break.

My most recent ( mid 2025) SWU on BA experience was interesting; I had shared/asked for opinions here. Cleared the SWU months before, but when I called for something unrelated, they told me I never paid YQ, which no one ever asked me to pay and my flight was ticketed. AA said my flight was invalid as I never paid the YQ (that they never asked for). BA didn't say a word and I flew event-free.

The weird part is that this continues to be so ridiculously variable when AA has supposedly clamped down extensively on the "whatever goes" GA era with SABRE. Of course, in classic AA fashion, they've neutered the good, while leaving the mess.

As anticipated, this ticket proved to be a headache to deal with during IROPS last night when it came to actually getting re-ticketed, however the one constant was my BA Y seat .