While certainly possible, it would take the pool of people able to build it down at least an order of magnitude. I can say so with the experience of a guy who b

While certainly possible, it would take the pool of people able to build it down at least an order of magnitude. I can say so with the experience of a guy who build drones and also tried working with some vision stuff for drone indoor positioning. It simply is far harder to do. GPS guidance you can do it in an slow evening. Most of the measures intended to stop access to explosives, weapons and generally dangerous things are not able to do so 100% but simply make the cost of that access high enough MOST malevolent actors will simply not afford it.