No point in learning TTools to add more AI traffic if you don't have any to start with.

The AI traffic is enabled from the FS2002 menu. I can't remember exactly how right now but Will's (Smoke2much) suggestion seems about right.
PS. A common cause of missing AI traffic is deleting the default.dp file from FS2002\AIRCRAFT by mistake. The AI traffic cannot work without this file. If it's not there you can retrieve it from one of the CAB files on CD-1 with WinZip.