I saw a file not to long ago that made my AI aircraft become overwritten and made into airlines such as KLM ,British....
Where can I get that file from..I tired of the default AI aircraft.

There is a download here  http://www.simviation.com/fs2004jets43.htm (4th one down) that will replace your default Boeing flights with Boeing and Airbus realworld airlines. Fairly easy install, but does require using Traffic Tools (included) to edit the traffic*.bgl file.

This does not add additional traffic only replaces the default. Also includes animated ground equipment while the planes are parked.

If you wish to add more traffic, or real world schedules, the most popular add-ons are from Project AI http://www.projectai.com/

Cheers,
Dave