The Undiscovered Country
or how to find missions near an airport you haven’t landed at yet.
When you land at an airport a circular area with a radius of about 80 nm shows up on the mission map as not dimmed and new missions originating at airports within that are will be available. Also, yellow icons representing the pilot and your airplane will be at the airport. It turns out that there is a separate icon for the pilot for a reason. 
Let’s say that you land at KBOI (Boise, Idaho, USA) but you want to fly out of KSLC (Salt Lake City). You could look for missions that would land at an airport that’s within 80 nm of KSLC or you could go to the missions map and zoom in close enough to KSLC for the airport icon to become clickable and click on Fast Travel.
Clicking Fast Travel moves the pilot to the airport, for which there is a fee, and reveals all the missions available in the area. If you own a company and want use a company plane, you’ll need to transfer the plane, for which there is a fee,
FYI - When you go to the My companies page, the Transfer Aircraft button will allow you to move the airplane to an airport that is in an area that is not greyed out (has been discovered). This is mostly redundant because when you choose a mission not based at the airport where your plane is already sitting, you have to move it anyway.
Cheers