Despite having plenty of A1 Traffic in the past, it has suddenly disappeared from all the airports. I have checked the Traffic Density settings and it stands at over 90%.
Can anybody please advise me how to recover it without reinstalling? It's pretty lonely at the moment. Airport vehicles etc are present and moving around.
Any help appreciated.  Dendoe

As suggested, check for the default traffic file, trafficAircraft.bgl. If it's still there.....

Have you added any new ai traffic files to your sim?

Most addon traffic*.bgl files are in FS9 format. While FSX can use traffic files in either FSX or FS9 format, it will not run them at the same time. If FSX sees FS9 traffic files it will run them and ignore any FSX traffic files , so the default ai will go missing. You would then only have traffic at/between airports used in the FS9 traffic file, not the global traffic from the FSX default.

The simple solution is to convert the FS9 files to FSX format. AI Flight Planner (AIFP) is a ai flight plannning program that can find FS9 flight plans convert the files from FS9 to FSX format-
http://members.shaw.ca/aifp/

Dave

As far as I know, there is no product called "A1" traffic. If I am correct, I suspect the poster misinterpretted the second character as a "1" instead of an "I" because they perhaps did not realize that AI stands for Artificial Intelligence.

Peter