Originally Posted by xliioper

C+ seats on DL book into separate fare classes than regular economy seats and aren't just extra legroom seats (unlike most other airlines like WS). As with FC upgrades, DL only allows one companion comp upgrade into C+ (using the C+ comp upgrade fare class/bucket SU). So they aren't quite equivalents. The only airline which has a true equivalent is VS and their "Economy Delight" seats which are similar to DL C+ and also are booked into separate fare classes than regular economy seats. Although VS does not have a comp upgrade program for Economy Delight seats (either for their own elites, or partners).