Hello, welcome to the fourms
for your question, look in your flightsimulator 9 folder's aircraft folder, usualy located here: C:\Program Files\microsoft\fs9\Aircraft.
Have a look in that folder and see if you can see a CFG file called "airlines" open it up in a program like "notepad" and see if it has all the airlines listed, its easy to add new airlinews just by adding a new line
hope this helps
James