The Virgin domestic services will be run on whatever Branson can get his hands on at the best possible price (but not a prop, London pax hate those). However, as always the problem will be, who makes the money? Any feeder service being ticketed by the long haul operator will never make any cash. I believe the old BA-CityExpress/BAconnect set up used to go like this: Ticket (for instance) Aberdeen to LA Via LHR, Total distance about 5800 miles, ticket cost, one way, say 300 pounds for arguement's sake. But, distance from ABZ to LHR is about 400 miles which is about 7% ish. So BA hand over to Cityexpress/BAconnect 40ish quid for their share of the journey (full service remember), no wonder they never made any geld.
I can't believe it would be any different under Virgin but it makes sense that Branson will use someone else on a wet lease for the first few years.