Ryan Calo appears on Talk of the Nation to discuss drones and privacy law:

Well Ari, you know, there’s very little in the way of American privacy law that stands in the way of drones. You know, there is no, for instance, reasonable expectation of privacy in public or from something viewable from a public vantage like your backyard. And on top of that, there’s no reasonable expectation of privacy in contraband.

And the reason that those two things matter is that that means that law enforcement largely is able to fly a drone around looking at public spaces, people at people’s yards, anything that’s visible from the air basically, and the Constitution doesn’t have much to say about it.