Drones are not hard to make actually. Its just a glider with a jet engine and high techology remote control.
Problems will be when they put nuclear heads on these things. Can you imagine if they get hacked before they reach the target.
Military probably has their own operating system but still risky.
The next threat will be stratosphere nuclear satelites. They can be lauched anywhere and send up to the stratosphere then travel around the earth almost undetected.
The stratosphere is around 13km high. Its a lot quicker to drop a nuclear missile from 13km than send a missile 15,000km.
