With thanks to @N316TS for pointing this out, if you want to have an AI Santa Clause in his Santa Sleigh flying around and parked at random airports then edit this file in notepad:
For the Microsoft Store install:
C:\Users\[Your User Name]\AppData\Local\Packages\Microsoft.FlightSimulator_8wekyb3d8bbwe\LocalCache\Packages\Community\orbx-aircraft-santa\SimObjects\Airplanes\Orbx_Santa\aircraft.cfg
For the Steam install:
C:\Users\[Your User Name]\AppData\Roaming\Microsoft Flight Simulator\Packages\Community\orbx-aircraft-santa\SimObjects\Airplanes\Orbx_Santa\aircraft.cfg
Search(Ctrl + F) for this line:
isAirTraffic=0
^ Change the 0 to a 1 and then save the file.