The new video for Amazon’s Prime Air serviceĀ  gives an idea of the state of the art, showing a small drone that can take off and land vertically, as well as flying like an aircraft at high speed. It can deliver a parcel weighing five pounds to an address ten miles away or more, flying at under the 400 feet altitude specified by the FAA and without direct human control.

The service relies on the drones being largely autonomous and with on-board intelligence; in the video a drone is shown with a sense-and-avoid system that steers around obstacles and plots its own landing. To be cost-effective, the delivery drones will also need to be cheap. Given that they are likely to be made in very large numbers, economies of scale are likely to kick in.

Of course, a system that can deliver parcels can also deliver bombs. Dodging around at such low altitude, the drones would be a challenge for most air defences — large numbers of them even more so. The technology that enables Amazon Prime Air will also enable Swarm Troopers.