framer
Planning the route, organising Dip Clearances, generating your own flightplan, organising your own ground handling, to name just a few that the average airline jock doesn't do. I'm not saying that they wouldn't be able to learn it, but frankly i would suggest that they wouldn't know where to start when the tasking order came across the desk that the the PM needs to go to Israel in 3 days.
But on the other hand, for the mundane domestic VIP stuff, an average airline 737 driver would cope perfectly well with a bit of indoctrination.
V