1/ A Drone may not injure a human being or, through inaction, allow a human being to come to harm.
2/ A Drone must obey the orders given it by human beings except where such orders would conflict with the First Law.
3/ A Drone must protect its own existence as long as such protection does not conflict with the First or Second Laws.
Great, now all we need is the Zeroth Law:
0/ All Drone Manufacturers should include an AI clever enough to successfully interpret the other three laws.
This may take some time...