With me it's more often the sound file reference.
The quickest way to get the game running again is to text edit the game.xml file.
Change ShowUIWorld="true" to ShowUIWorld="false", and it will ignore the error and start.
Then you can select another aircraft and all will be well again.
Once you've fixed the issue with the offending aircraft, you can set it back to true again.
...I downloaded some AVH aircraft from here but when I went to use them the game crashed.