If the passengers simply want to get from A-B then a company like privatair is not the answer. If they want to do it with bells on then an airline style service may not necessarily be the answer either. It realy does depend on the client.
I work for a major schedule airline who have worked deals with private companies so that the service runs regardless of booked pax, the customer pays the costs plus a bit. Everybody is happy!
Surely Lufty could sort something like that out the system works, honest.