Cl300
Airpartner and vistajet and lufthansa pj and other charter based membership programmes also guarantee availability without having to run a huge fleet overhead.
There are 2 ways to run a programme, the netjets heavy overhead model, or a membership programme can also run as well if not better using managed chartered jets.
In fact the charter fleet is now offering young capable aircraft Which nje don't have
Such as sovereign, cj3 etc.