I'm looking at LGA-ATL-FLL next Friday (the 14th). DL1745, DL726.

I check expertflyer.com and I see F0 Y9 B0, F0 Y6 B0 respectively. I was thinking well holiday weekend leisure travel to Florida==makes sense. Then I check Delta and I see they are selling F seats on the same flight for $1794 full F not a discount first ticket. Also, EF.com shows Y only available in economy yet DL.dumb will sell me a Q fare for $729 rt

So why does DL differ from EF.com? I'm well aware that delta will often times sell more seats in a cabin even if every seat is taken because they still come out ahead in the end after VDB etc. But I always thought they reported the correct number of seats for sale in each cabin to EF.com etc.

Stranger, and maybe this is key. If you search EF for LGA-ATL & ATL-FLL seperately you get different results. very different. F3, F9 etc.

I'm hoping the experts, including the EF representative, will chime in here, but what I understand is that EF shows bucket inventory while delta.dumb shows tickets available for purchase. For example, there could be sLUT seats on a flight (EF) but no sLUT fares (DL) because advance purchase sLUT requirements cannot be met. However, in this case DL would allow sLUT SDCs because the inventory is available.

Your example, however, is indicating the reverse of what I would expect, so maybe EF isn't totally up to date on availability.

Neither source shows actual availability of seats, although internet DL sources can apparently see load factors and compare that to the numbers of coach and FC/BE seats on various aircraft.

Your last paragraph suggests a married segment issue, which I hadn't thought EF reflected. AFAIK EF just shows inventory segment-by-segment, for instance listing two connecting segments on different lines so that you can immediately see which flight is the problem. I'm not even sure how you can make EF display inventory for an entire connection, as the first line of your OP suggests, versus segment by segment.

At first I thought I understood but now I'm puzzled too....

Have you tried to contact EF and ask them to look at this example?

I believe that EF shows availability by segment. Will DL sell F (or Q) on the individual segments? DL "logic" might be willing to overbook for a sale of both segments, but not either one individually.

Please recheck your search because your flights don't match. DL 1745 on 2/14 is from SMF to MSP and DL 726 isn't scheduled for 2/14.

ExpertFlyer will show the inventory however the airline returns it, if that includes married segment logic by the airline, then we will reflect that. That has always been the case for airlines that use married segment logic.

You can see availability segment by segment by doing a Flight Availability search for just that segment, however it won't reflect any married segment logic that the airline may apply.

I have not; I will if they do not chime in here. I initially thought it was an error or change in they way DL was reporting inventory to EF.

like you called out MSP, I think it must be an issue with the segments since I get different results if I search segment by segment. Makes perfect sense that DL would be charging a high price for NYC snow birds wanting to get away for the weekend. Hello FLL. I booked weeks ago!! lol