A few points on the above:
- There are domestic cabins marketed as "Business Class" for which complementary upgrades are available. Additionally, some Caribbean and C. America flights are complimentary upgrade eligible and marketed as "business class". They don't feature the lie flat seats, however and aren't marketed as Delta One.
- There are some flights with a Delta One cabin (SLC-HNL, ATL-LAX for example) that are complimentary upgrade eligible (though the service isn't marketed as Delta One the hard product is the same)
- On some international flights Delta sells C+ seats as a seat add fee. On others (namely the Pacific and S. America), W is a separate fare class.
Thank you for the clarifications. Generally speaking however, the domestic flights which are upgrade eligible and flown without Delta One service but in a Delta One cabin (ATL-LAX etc) are marketed as First Class.
Which Central America and Caribbean flights have recliner seats but aren't marketed as First Class? For example, ATL-BOG and ATL-SJU are both marketed as First Class. They only show up as Business class if they're booked as part of an itinerary (TATL for example) that includes Delta One. Either way, they're upgrade eligible.