Private jet charter is priced for the whole aircraft, not per seat. That one fact explains most first-quote surprises. A one-way trip is not half a return. An empty aircraft still costs money to move. And two extra passengers barely change the price.
The base of any quote is the aircraft’s hourly rate times its block time (engine start to engine stop). It is not the published flight time between two cities. Block time includes taxi, holding and the real route flown. So a 55-minute flight is rarely billed as 55 minutes.
Positioning (flying the aircraft to your city) most often explains a gap between two quotes. Every aircraft has a base. If it is not at your departure airport, the flight that brings it is part of your trip. If you are not flying back, the flight that takes it home usually is too.
So a quote from an operator whose aircraft is already near you can be much cheaper. The other operator may be flying the exact same aircraft type across the country.
Airport charges come next: landing, parking and ground handling. Each airport sets its own, and they vary widely. A metro airport with full handling costs much more than a regional airport. An overnight stop adds parking.
Crew duty is a legal limit, not a sales choice. Crews may only work a set number of hours. If your day runs longer, you need a second crew flown in to meet the aircraft, or an overnight stop with a hotel. Both add to the price, and neither can be negotiated away.
Ground waiting is charged because an aircraft waiting for you cannot fly anyone else. On a site visit or an event, waiting can be the largest single line. A four-hour hold is four hours of the aircraft’s day.
Taxes and statutory charges are added on top and depend on the type of flight. International flights also add permits, clearances and handling that domestic trips do not need.
Two quotes can only be compared when both list what they include. A lower hourly rate without positioning is not a better price. It is an incomplete one. Ask each operator to show the same items. That is the fastest way to see which is really cheaper.