Originally Posted by
Gertjaars
Im a Gold medallion. I got my free international 1st class upgrade in app from ATL-GUA, I booked initially in C+.
1st class was sold out by the time I checked in so I'm glad I booked in C+ initially in order to get the free upgrade to F.
So yes.. DL does upgrade you for these international routes to 1st class.
FYI, booking C+ doesn't give any priority over main cabin for F upgrades. C+ have an underlying coach (main cabin) fare class. This is what it goes by. This is usually (not always but usually) the same fare class you see available for booking main cabin.
C+ is not Premium Economy. If at some point DL starts offering PE on domestic flights (likely only JFK-SFO/LAX if were to happen) then booking PE would give priority.