Battery life. And noise. And carrying anything substantial. And adding all the safety mechanisms that prevent it from killing someone in case of malfunction. An

Battery life. And noise. And carrying anything substantial. And adding all the safety mechanisms that prevent it from killing someone in case of malfunction. And mechanisms to prevent it from being stolen or damaged. And autonomous navigation in case of unforseen obstacles (a construction crane?). And the ability to either land or negotiate a delivery point (imagine an urban road, with tall builings, walkways and traffic). And the ability to coordinate with other autonomous drones (avoid collisions, etc.). I do fly a drone for fun as well. Last Christmas I had the idea of flying it over the frozen surface of a mountain lake, not far from my hometown. Well, about 30 seconds in, a pretty angry buzzard made a straight line for it and crashed it. It weighs about 2.5kg, it crashed on the ice from about 10m. No major damage, but retrieving it from there was, well, tricky :) Here you can see an eerily similar incident: https://www.youtube.com/watch?v=OTTiLXYMAZk https://www.youtube.com/watch?v=OTTiLXYMAZk