It won't be long until U.S. airspace is buzzing with unmanned aircraft, or drones. Not a few here and there, but many. We tend to equate drones with the stealthy aircraft used by the military to conduct surveillance and launch strikes against enemy targets overseas, but they are capable of much more than that.

Domestic law enforcement surveillance, firefighting, humanitarian relief, border security and scientific research are just some of the possible uses. We're not likely to see drones of the armed variety over U.S. skies, but even that, too, is a possibility. In any event, it's clear that a number of issues can and will arise out of the sudden preponderance of these versatile aircraft.

One is privacy associated with air surveillance, both on the part of law enforcement and commercial entities. Another is the sheer volume of new traffic. Safety concerns presented by remote-controlled planes, some potentially weighing more than 7 tons, are not to be discounted.

Last week, federal officials took a major step toward opening domestic skies to drones by soliciting proposals to create six drone test sites in the U.S. The testing will presumably study how drones and traditional, manned aircraft can coexist in the same airspace. Privacy advocates have a very different concern about the rapid and widespread acceptance of the technology: Many worry that an abundance of drones will create a "surveillance society" in which Americans are routinely scrutinized.

All of this invites the question: What steps is the Federal Aviation Administration prepared to take to ready America for this drone invasion -- an invasion likely to launch a multibillion-dollar industry? It's not just a logistical question; legal and constitutional ramifications exist here as well.

How are we to be assured that the links between the drones and the on-ground operators flying them are secure? What protections against the possibility of drone-hacking by thrill-seekers or terrorists need to be established? How easy will it be to obtain a license to fly a drone, which can be as small as a hummingbird or as large as a 15,000-pound Global Hawk?

Drones are already in use in U.S. airspace, just not yet in the numbers expected after 2015. The Border Patrol uses them on the U.S.-Mexico border, and several hundred police departments, universities and government agencies have been issued FAA permits. In fact, Fresno State University recently applied for a permit to use unmanned aircraft to survey valley farming operations. The few hundred drones operating now are a drop in the bucket compared to what is likely to come. Power companies, farmers and ranchers, film crews and news organizations will be interested.

To what extent can federal officials guarantee the safety of our skies, and can Americans be assured that their already rapidly disappearing privacy rights will be protected? These discussions deserve much more attention than they have received, and soon, because once the drones are out of the barn, it'll be vastly more difficult to herd them back inside. Our privacy and safety are at stake.