FS9 ai traffic files will cause FSX to ignore any FSX formatted ai traffic files, including default ai air traffic and the ai ship and ferries. The FS9 files can be easily converted to FSX format with a couple of utilities.
Flightplan BGL Converter, is a simple to use converter. Unzip to a folder of your choice and run the .exe file. There is no help file, but it's pretty self-explanatory.
http://lc0277.nerim.net/wiki/index.php?software-bottom of the page.
AIFPC, is a compiler/decompiler, similar to TrafficTools, that works with FS9 and FSX ai traffic files. It decompiles to a TTools .txt source file set, (which you can edit if desired), then compile in FSX format.
http://www.fsdeveloper.com/forum/showthread.php?t=4746&highlight=AIFPC&page=3-download link in message #57. Help file included.
Dave
At that time [1909] the chief engineer was almost always the chief test pilot as well. That had the fortunate result of eliminating poor engineering early in aviation. Igor Sikorsky
I intend to live forever....so far, so good. Steven Wright
You know....you can just rip up a to-do list.