You have to switch your frame of reference when you're dealing with fractional flying. There is no scheduled service. You fly from where the owners wants to fly from and take them where they want to land, as long as it's safe and you can comply with all the rules. It's common for owners to use the smaller, outlying airports to avoid the departure and arrival delays inherent with larger, busier airports, but some still choose to use airports like LGA, IAH and LAX, especially if they are making a connection to/from a commercial flight.

-NTFB