A loyalty program for this kind of thing is going to be tough, since your customers are paying more for one trip than most people on FT spend annually. Unless you give them a free trip, it is going to be hard to use smallish freebies to motivate someone who can afford a private jet.

Also, airlines run loyalty programs to give them a competitive advantage since their prices are mostly fixed to those of their competitors. No such thing in private aviation since it's prices are negotiated.

One last thing. You want to make sure that whatever incentives you have in place are there to motivate the purchasing decision makers. Showering the passengers with goodies won't really help if they don't have authority over the purchase decision.