https://www.techradar.com/news/amazon-patent-reveals-delivery-drones-could-have-facial-and-gesture-recognition

Amazon would probably like to just parachute packages to you from a safe distance. But the company's latest patent suggests it thinks it might be safer to just fly drones directly in front of customers instead of risking broken Amazon Fire tablets (or concussions). 

To potentially aid in this, the retail giant has filed a patent for a package delivery drone with a sensor system for registering both “visible” and “audible” gestures. Drones will communicate with a gesture database that will help it to recognize what you’re trying to get it to do, like “Fly over there!” or “Back off!”