The initial position setting should have been modeled as a one to one relationship to airport not as a single global position. That is users should be able to set the initial position on an airport by airport basis. The problem with the current setup is that an initial position is a global position that applies to all airports and the only way to select another airport is to either remove the initial position settings or input a new one for the airport I want to use.
I would like to set this up so that I start out off of the runway like you would if you were flying a real aircraft and taxi to the runway for takeoff. To do this you have to use an initial position. The problem is that I can only set one initial position and switching airports is a real pain in the backside.