Pardon my ignorance in all things C# or perhaps for stating something that has already been tried but if you have a script that destroys aircraft can't you use a sleep command to pause execution? e.g.
Thread.Sleep(6000);
I'm not a software developer and get by with most of my server scripts written in 'lowly' bash
so I could be completely wrong here with the above command.
A minutes delay to allow the pilot-less plane to crash and burn would be cool though and would clean up the server too.