From X-Plane SDK
XPLM_API int XPLMAcquirePlanes( char ** inAircraft, /* Can be NULL */ XPLMPlanesAvailable_f inCallback, void * inRefcon);XPLMAcquirePlanes grants your plugin exclusive access to the aircraft. It returns 1 if you gain access, 0 if you do not. inAircraft - pass in an array of pointers to strings specifying the planes you want loaded. For any plane index you do not want loaded, pass a 0-length string. Other strings should be full paths with the .acf extension. NULL terminates this array, or pass NULL if there are no planes you want loaded. If you pass in a callback and do not receive access to the planes your callback will be called when the airplanes are available. If you do receive airplane access, your callback will not be called.