MacOS Catalina (macOS 10.15) introduces new requirements for apps. It also drops support of 32-bit apps, such as Plane Maker 10, entirely.
Catalina & X-Plane 10
If you are using X-Plane 10, we recommend that you do not update to macOS Catalina. The X-Plane 10 installer, Plane Maker, and Airfoil Maker apps will no longer work on this version of the Mac operating system.
Catalina & X-Plane 11
While X-Plane 11 is compatible with Catalina, a number of users have reported problems with third party add-ons and Catalina’s increased level of software security. If your X-Plane 11 setup is heavily enhanced with add-ons, you may want to remain with Mojave.
The X-Plane 11 Professional-Use USB key will require updated HASP drivers, available here, to work on macOS Catalina.