An empty-leg is a trip that the aircraft makes without having scheduled passengers for it, such as when the aircraft must return to its base after a trip. Empty-legs are, by definition, one-way trips and they can be booked at a lower cost - but they do not offer the same flexibility as a regular charter trip that is fully based on your own scheduli

No. When you charter a private jet for personal or business use, you rent the entire aircraft the price does not vary with the number of passengers. Utilizing the full capacity of the aircraft greatly renders private jet air charter trips more cost-effective.