Hit my Limit

Today I discovered that there is a limit to the number of aircraft you can have in FS9.
Not sure what the exact number is, but after installing about 20 new planes last night, I noticed that none of them had showed up in the sim, so I cleaned out a few of the ones I had tried and didn't like, and then the new ones appeared as they should.
Now I have new problem boggling my mind over this. My aircraft folder in the Config file location is now full of aircraft I no longer have installed, is it safe to delete the contents of this folder to let FS9 rebuild it, or must I take out only the ones I no longer have?
I guess 25GB of aircraft was just too much for the poor sim to handle.
Thanks for any help.

Now I have new problem boggling my mind over this. My aircraft folder in the Config file location is now full of aircraft I no longer have installed, is it safe to delete the contents of this folder to let FS9 rebuild it, or must I take out only the ones I no longer have?
I guess 25GB of aircraft was just too much for the poor sim to handle.

Thanks for any help.