The solution is actually easy but it’s easier said than done, just remove the gates/parking parameters on the gates that they use to place the static aircrafts.
For example, if the airport has 50 gates to choose from. And they place 40 static aircrafts. Just disable the 40 gates that they use the static aircrafts on, and that only allows you 10 gates available for you to pick in the world map. The other 40 is just nothing, no white dots to click on, and they won’t appear in the drop down list.
But this requires an actual edit of the airports themselves. Now for standard freeware content airports, it’s easy to do, because they can just duplicate the airport content place the static aircrafts and repackage the entire airport and deploy it. But it’s also subject to future updates. If Asobo updates the freeware airports, they have to redo the whole process, repackage, and redeploy as an update.
For payware airports. This is probably almost impossible to do, since the airport contents are encrypted so you can’t really make changes or edits to the gate assigments or availability on the airport parameters themselves. They could only place objects as world objects that gets superimposed onto the airport. But that’s going to be the problem.