Reading in other forums, it seems to be the reason DL/VS are opening JFK and BOS routes from Gatwick next year is the likelihood of Jet Blue launching their London operations from the airport, and they are keen to give them some competition on the routes.
I've not heard Jet Blue are definitely launching the transatlantic routes from Gatwick, but it seems DL and VS are making it clear they will have a fight on their hands!
Another blow for struggling Norwegian too!