I'm guessing all it did was fly around loosely controlled if at all. The miniaturization is impressive, but they were not likely able to do much more than a sm

I'm guessing all it did was fly around loosely controlled if at all. The miniaturization is impressive, but they were not likely able to do much more than a small internal combustion engine in the 70s. Today however I would not be surprised if such devices exist and are in practical use.