You'll be surprised to know that scheduled airlines don't even use many airports across the country. Moreover, most of these operate their flights between odd major hubs. On the other hand, charter operators use these these odd hubs. So chances are bright that one airport is closer to your point of departure and arrival than the closest major airport. Even before you begin your experience of the convenience of flying charter aircraft you can make personal and business trips simpler just by flying in & out of an airport closer to you. With thousands more arrival & departure points available, air-charter travelers can now significantly cut down on time getting to and from the airport.
A majority of the airports available for general aviation are private - though almost all are available for public use. These are chosen on the basis of runway-length and services that may them practical for charter travel. The air charter operator or broker you select should help you in choosing an airport, since working out the suitability of the airport becomes is their responsibility once the actual flight plan is filed.
There is more thab just timesaving. Usually General aviation terminals are designed for comfort & convenience of a smaller number of travelers. They would take security as seriously as at larger terminals -- but you will never find a line of 150 passengers waiting in a queue at a metal detector in a fixed based operator (FBO). Its also possible that you'll be the only person in line. You might not find a lounge, comfortable chairs, a TV or magazines while waiting for your flight crew to find you. Chances are the crew will be waiting for you.