I don't think security is a real issue that can not easily be dealt with, similar or more damage can/could be done hacking into cars and trucks computers.
Good
Bend a lot, it would appear you have solved all the Middle Eastern problems then? Not to mention the terrorist's avowed aim to wipe all non believers off the face of the earth if they don't convert to Islam.
Relative has been involved in the testing of drones of all sizes for military purposes, without any terrorist input the crash rate is high, sometimes due loss of control brought about by nothing more than a disturbance of radio signals in the atmosphere.