XPLM_API void       XPLMGetNthAircraftModel(
                         int                  inIndex,    
                         char *               outFileName,    
                         char *               outPath);    

This function returns the aircraft model for the Nth aircraft. Indices are zero based, with zero being the user’s aircraft. The file name should be at least 256 chars in length; the path should be at least 512 chars in length.