You're right ! Look no further than mounting Stingers on OH58Ds. Add to this , certain aircraft have fairly small radar signatures and if shadowing a B747 ,it's easy to not even see it. You and I both know that jettisoning the launchers would be fairly easy as well . What most people don't realize is tha tthe warhead for any kind of SAM ,or any other anti air missile ,does not have to be all that large, either.