The Federal Aviation Administration estimates that in 2017, there were 1.2 million commercial and hobbyist drones in the US. By 2022, they expect that number to more than double, to 2.9 million.

That's because drones are enormously helpful. They can create beautiful aerial photography, help fight fires, detect leaks in oil and gas pipelines, and deliver medical supplies where road access is limited.

While most drone operators fly in good faith, bad actors can do tremendous damage. At the extreme, militias, drug cartels and others are using commercial and consumer drones as weapons.

In January, The Associated Press reported, Houthi rebels used a drone equipped with explosives to attack people at a military parade killing six in Yemen. And last summer, assailants used drones armed with explosives to attack Venezuelan President Nicolás Maduro at an event where he giving a speech outdoors in Caracas.

This weekend, unauthorized drones buzzed over the stadium that will host the Super Bowl this Sunday, proving a nuisance to law enforcement in Atlanta. Meanwhile, drones are increasingly disrupting air travel.

While regulators and legislators hash out the new rules around drones, a handful of companies are trying to ensure safety with "counter-drone" tech.