JUst installed this software which as stated, populates airports with airliners, especially the ones supposed to be there (AF in Paris, JAL in Tokyo and Delta in KATL...)
The only problem is the amount of planes flying all over the place in big airports. Maybe this can be fixed in an update
Other than that the program was freezing FS2020 when trying to start a flight at Orly (LFPO). I realized that I had a mod installed for Orly, I removed it and Simple Traffic worked as expected...
So first thing to do if Traffic does not work (or crashes FS2020) with a specific airport, check if you do not have an add-on for this particular airport and remove it
Otherwise despite the agitation in the air over the airports, ST is a great and affordable program... Danke schon Aerosoft!
J-Louis