Crediting Delta Flights
 

First, I'm not sure if this belongs here or in the Delta forum, so sorry if it's in the wrong place.

I have Flying Blue that will expire soon so I'm planning to take a short flight to keep them alive. It looks like I can do this by crediting a Delta flight, so that's nice. I have platinum status with SkyMiles so if I book through my account I can get a "Comfort+" "upgrade" immediately and I think I can change the FF number to my Flying Blue account after. But if I do this, the booking class shows as SU and I'm concerned this would affect the miles crediting to FB. I can't find an answer to this exact question here but from what I've read FB will use the underlying fare class and it shouldn't post a problem.

Do any of you wise forum sages know if this will be a problem or if I'm just being paranoid? Thanks in advance.

Fair enough, especially since the flight is under 3 hours. Though now I am kind of curious if anyone knows if it's possible to pull this off.

You will be downgraded as soon as DL determines that you did are not eligible for the seat anymore and you did not pay for the seat. In the past, this would happen if there was an equipment change, but there have been reports of passengers losing their seat assignment once DL determines that they are not eligible.

For crediting purposes, DL reports to FB the fare class you purchased even if you are upgraded. Even if you buy a comfort+ seat during the booking process, it will not book in W but in an underlying fare that DL will then report to FB.

The problem is not with how much the flight would earn, but where the miles end up.

As the OP is crediting the flight to FB solely for the purposes of keeping their FB miles alive, the proposed strategy is incredibly foolhardy. They need miles to post to FB and don't care about how many. But equally, they should NOT be "polluting" the booking with their Delta number in case that is where the miles post.

Completely agree. I have a FB account that I use to earn miles through my AF Amex and in the past I got a flight credited there because somehow my FB number ends up in my PNR when importing flights to my AF profile. So always better to keep the process simple.