The deal for RDU, if I understand what you said about PIT correctly is a little different. Right here in the area of RDU, we have the Research Triangle Park (RTP), a large business and research center. The companies in the area put of the money to subsidize the route.
Currently RDU’s only trans-atlantic flight, a daily AA 763 from RDU - Heathrow, is paid for this way. American could depart this flight with no one on board an break even due to the backing they receive from local business.
It’s been speculated that this new Delta flight to CDG will work the same way. The president of the group providing the backing for the AA flight was also at RDU for the announcement of the Delta flight.
The new delta flight brings the total for RDU to 4 international destinations.
Air Canada - 3x daily CRJ to Toronto
American - Daily 763 to London, Heathrow
Delta - Saturday only MD88 to Cancun
Delta - 5x a week 757 to Paris, Charles De Gaul
GlaxoSmithKline just announced that they are consolidating their entire North American headquarters to their facility in RTP.