I'd be surprised if Delta and Virgin both operated MAN-JFK,
So would I, especially if the rumours of Norwegian possibly joining the fray next year turn out to be true
the opportunity is to up capacity and cut costs by using VS metal and redeploying the Delta aircraft.
I wonder if Delta would try a new route from MAN with the redeployed 767, like Detroit for example. That would give the DL/VS combination a pretty comprehensive offering between them with JFK in the east, ATL in the south and DTW in the north, plus the VS leisure routes.