What "private buyout" means here
The coach is yours for the contracted window. No public passengers, no other charters mixed in, no sharing of the schedule with another group. You pay for the vehicle, the driver, and the time window — and you control what happens inside.
This is different from a regular charter only in degree of exclusivity — the same vehicles, the same drivers, the same dispatch process. The difference is that the booking confirms exclusive use, including hold time, idle, and multi-stop flexibility built into the contract from the start.