Are drones really on the verge of delivering packages to your doorstep?

Amazon says it is ready to fly deliveries by drone as soon as federal rules allow but experts suggest technological intricacies still need to be ironed out

How far away are we from a world where drones deliver packages? If Amazon is to be believed, not far at all. Others are not so sure: technical progress past this point isn't merely a matter of invention, it's a matter of public safety.

Related: Congress warned that drones present 'a nightmare scenario for civil liberties'