Originally Posted by
SPort
When I phoned AF regarding another matter today, I was told that because my originating flight is on DL, check-in would be 24 hours prior, not 30.
It doesn't have to deal with it being DL, but that the flight is departing the US (including it's territories). US regulations limit check-in to 24 hours before departure of the first flight. Connections can be outside the 24 hour limit as long as on the same ticket. Even if your first flight was operated by AF you couldn't check-in till 24 hours before.