Thanks for pointing that out, I was unaware of this setting.
The Santa Sleigh contains an ai.cfg file so it should be good to go.
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 and then you should have an AI Santa Clause in his Santa Sleigh flying around and parked at random airports.