You mean low enough to the ground to be undetectable - and there is already hobby-level advanced technology to do this out on the intrawebs. I myself am buildi

You mean low enough to the ground to be undetectable - and there is already hobby-level advanced technology to do this out on the intrawebs. I myself am building drones (planes, mostly) to do things like auto-navigate the neighborhood and so on, and am actively seeking ways I can get involved in a startup to use this technology for positive effects. I'm not at all surprised to see the drug cartels already making headway on carrying loads - there are a near infinite number of other good applications of this technology, which I sincerely hope governments allow to prosper, anyway, in spite of this ...