The B/E equipped planes are being put into service on international routes where they generate true B/E revenue. Delta has some new international service (e.g., ATL-SVO) and has some seasonal expansion for the summer.

After the summer, some planes will return to domestic service. All planes rotate through the schedule, often on a six-month basis, so that DL can perform periodic maintenance, etc.

There is NO marketed domestic B/E service any longer: DL used to market the JFK-LAX route as B/E, but that stopped a few years ago, and non-B/E mainline will vanish from that route (still amazing to me that DL was losing money on this lucrative route) in a few weeks.