Today, technically, anyone could have their own air force with drones. And that's becoming a serious problem to security experts.
Last Sunday, three drones armed with explosives were used in a failed assassination plot on Iraq's prime minister.
Analysts say they resembled drones linked to Iranian-backed militias, which have targeted American troops in a spate of attacks in Iraq. Another flurry of drones descended on U.S. forces last month in Syria -- and they’re also thought to show Iran's hand.
"Iran has been building drones for decades, but in the last few years it's really realized that drones are an easy machine that you can kind of disassemble, move across borders, teach proxies and terrorist groups how to use them and basically encourage those groups then to attack Americans or other U.S. allies," "Drone Wars" author Seth Frantzman said. "And then it's very hard to blame Iran itself because all Iran can say is, 'Well, yeah, but you found a bunch of pieces of a machine. There's no evidence that we did it.'"
Frantzman says Iran often uses so-called "kamikaze drones" for one-way suicide missions. They might even be as large as a person, but little is truly known about Iran's drone program.
"We have not seen nearly enough information about the cost or the scale of the program, which means we don't even know how many are being made a year," Frantzman said.
For now, they are mostly a threat in the Middle East, but some people, like the CIA's former chief of counterterrorism, Bernard Hudson, say weaponized drones on their way to the United States.
"In a country like ours, which is sort of increasingly ridden by political division, it will not be surprising if you're going to see people who at least consider, if not use, these cheap and readily available systems to carry out their own domestic violent agendas," Hudson said.
He's now CEO of a drone technology company called Looking Glass. And he's most worried about quadcopters, which are hard to detect, since they fly low and can weave around buildings. Hudson says large, public gatherings and airports are more vulnerable than people think.
"Right now, there is no existing, easy technology that's been deployed at U.S. airports to stop somebody from maliciously attacking an aircraft at take-off or landing," he said.
The Federal Aviation Administration says it's receiving more than 100 reports of drone sightings each month. In the energy sector, an intelligence bulletin first obtained by ABC News reported that a drone targeted a Pennsylvania substation last year.
"Historically, the protection of the U.S. power network has always focused on ground-based threats, somebody trying to walk past a perimeter, driving through a fence line," Hudson said. "They are not designed to stop threats from above."
The FAA tells Newsy it's crafting a process so certain facilities can apply for airspace restrictions and energy infrastructure would fall under that provision.
But the government is moving slower than the technology advances: The FAA just began testing drone detecting systems at a handful of airports this month. The Defense Department started evaluating commercial devices to intercept small drones in urban settings at a demonstration in Arizona this past spring.
Drone experts say demand will rise but the counter-drone industry is just taking off.