I had a 6-hour layover in JFK in December connecting to a VS operated flight (DFW-JFK-LHR) and my luggage was interlined without any problems and the status was in the app as to where it was and when loaded onto the plane/offloaded etc . If you don't have the app, download it. I personally feel like collecting the bag and then re-checking it is more of a hassle than I would want to deal with.