I'll Register My Drone When You Have to Register Your Gun
motherboard.vice.com
motherboard.vice.com
The registration of drones is quite literally only because of how heavily regulated NAS is and it allows the government to grab a little more power and a little more metadata about its population.
Note: I am not pro-drone registration either.
Not to mention that at the time of the Second Amendment's writing gun technology was primarily limited to muzzle loaders. If you want to argue that modern cartridge loading guns get grandfathered into an "ownership right" implied by the Second Amendment, then lets argue that drone technology is also a new technology development that is equally likely to fit within some auspices of the right to bear arms (or the right to a free press in view of camera drones) and thus is equally a so-called "defined right".
The same way freedom of speech was written in before the advent of the internet.