I am not from Laminar Research; just a flight simmer from down under.
If you look at the file structure of the X-Plane directory you will not file a sub directory for airports. But, you will find a subdirectory for scenery. Airports are part of the scenery files.
In answer to your first question within your last sentence I am of the opinion you will need to run the x-plane installer file again and deselect all of the scenery files which means you have no scenery at all.
In answer to the second part I am also of the opinion that you need to run the installer file again and select the scenery you want and deselect the scenery you do not want.
You may chose to read the User Manual and in particular the following section found at https://x-plane.com/manuals/desktop/#theairportscenerygateway
Others may have an alternative solution to your problem.