>Good, how?

Well, if we assume that the drone is pilotless up to the point when the drone needs to land:

* the drone flies to the GPS point in question and hovers pending instruction

* the drone takes a picture of the ground area and sends it via 4G to a controller

* the controller identifies a landing point and transmits it back to the drone

* the drone uses its obstacle avoidance systems to land, drop the package, and take back off for a return to Amazon's center.

This is just one idea. Perhaps Amazon provides you with a beacon for the drone, or you get a big QR code for the drone to target your house & they don't need pilots at all. Who knows!

Either way, it seems to me that the most interesting thing would be the collision avoidance systems for automated flight. But considering Google can do this with a car on highways, I'd imagine that a slow moving drone that can also operate along the Z axis would be easier.

> Flying military drones is a very complicated matter.

I'm sure it is - but military drones have an incredibly different mission; comparing them to a slow package delivery drone isn't really worthwhile. Hell, according to Wiki the Predator drone's stall speed is 60 mph - Amazon drones sound like they will be much slower, at least at first.

Do I misunderstand this technology? I think the fly to GPS waypoints thing is done by these guys: http://copter.ardupilot.com/

See this: http://copter.ardupilot.com/wiki/planning-an-apmcopter-missi...

The flight is manually pre-planned. You also need to consider obstacles (and other aircraft).

High latency's hardly going to be the end of the world for a slow-moving, low-mass n-copter that can just sit where it is during a lag spike.

I think the point the parent was making was lack of real-time feedback for the pilot.

Yes, my point was that such a device is going to be relatively easy to fly remotely even over a balky, high-latency connection. (Except perhaps in high winds, but high winds are likely to ground these things anyway.)