EK777 - I don't mean to be nasty, and it's gratifying to see someone so keen and coming up with ideas, but I just don't see a NCL-MAN route happening. If on the other hand you could persuade LH that there is a case for NCL-FRA...
You say that, but in a different model, LH operate really short sectors, such as NUE-FRA and STR-FRA feeding their hub. It is amazing considering the ICE rail connections from FRA's front door to both cities, but for whatever reason it fits LH's model, and LH make money.
I am however inclined to agree in the case of NCL-MAN as FlyBe wouldn't be feeding their own network, but a variety of code share airlines, so wouldn't be able to allocate long haul revenue to the domestic to massage the numbers, and make the STR-FRA leg look profitable - if indeed that's what they do, or what they want to do.