You can take a look at my scenery map below. Please note, not all airports are installed all the time. The map is purely to show which airports I own scenery for in P3D. The map is updated whenever I purchase scenery for a new airport.
If you'd like to see a list of the addons that I use for P3D, including ORBX coverage areas, you can see this on the "Addons" page inside the "P3D" dropdown menu above.