Take a ju88 up with no bombs and you can't calibrate the bombsite, nor can you open the bomb bay doors (it says "Your plane doesn't have any bomb bay doors").
It has an empty load for internal in case you just want the heavy external load. It has the empty external load in case you just want the light internal load (save on drag/weight). So you can't remove those options. Might want to add a few lines of code to catch that. No biggie, but I was going to practice calibrating offline and it wouldn't let me because I had no bombs.
