The only time they should be using private jets is, if it is emergency situation, say, a train derailment, and you need to get there ASAP and no commercial flight is available within reason, or you are traveling to a destination that does not have frequently scheduled commercial service.
Other than that, they can book an economy seat on Delta, Southwest, JetBlue, etc. Like anyone else. If they want to upgrade, they can pay for it out of pocket.
I would just as soon they stay home with a deck of cards and play solitaire all day every day. The self-important bastards do more harm than good wherever they go.