In an era where it seems that some pilots can barely control one drone, some companies want to operate dozens or even hundreds at a time.

Companies like Intel Corp. , Alphabet Inc.’s Project Wing, Qualcomm Inc. and Walt Disney Co. are working on technology to make it possible for dozens and even hundreds of drones to fly together, operated by a single person. The drone industry calls them “swarm drones,” and you might have seen them operating in fireworks-style shows at Coachella or Walt Disney World, where hundreds of Intel drones flew over the skies of the famous entertainment spot. They most famously performed behind Lady Gaga in the Super Bowl.

You may have thought Intel’s drones flew over the Super Bowl. But due to complicated technological and legal hurdles, they were actually just superimposed on your TV. Courtesy of Intel

But those drones weren’t actually performing behind Lady Gaga. The entire segment where drones created shapes of the American flag and Pepsi logos was actually prerecorded and superimposed on television so the drones wouldn’t have to do complex maneuvers over thousands of people in the stands and nearby.

That is the big issue for swarm drones, which could make specific tasks—including data gathering and delivery—more efficient, but are causing a legal and technical headache.

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The Federal Aviation Administration won’t allow any aircraft to fly near stadiums during major sporting events for safety reasons, out of fear that two drones might accidentally collide and crash into a crowd. Swarm drones have flown over other non-sporting events, but only sort-of. Disney flew drones over its Disney Springs shopping center, though the drones never flew directly over people.

Despite the hurdles involved in making swarm drones legally happen on a wide scale, companies are pioneering ways to use swarm drones to take over jobs too difficult or costly for humans. The FAA currently makes swarm drones illegal, unless the company receives a waiver of approval.

One of the hundreds of Shooting Star drones that Intel has used to fly over events such as Coachella. Courtesy of Intel

One of those companies is sending swarm drones over desolate forests in the Pacific Northwest. Unlike Coachella’s drones, these aren’t supposed to be seen; instead they’re supposed to drop seeds into the ground and spray herbicides. They’re operated by DroneSeed, one of 15 companies with government approval to fly multiple drones at once.

Each drone currently carries 25-30 pounds of herbicides, dropping between 75 and 90 pounds of herbicide in one flight. DroneSeed eventually hopes to have 15 drones in the air at once, but currently puts three in the air simultaneously.

“If you have a swarm waiver, you have one person handling three drones, which cuts down on labor costs and time,” drone lawyer Jonathan Rupprecht said. “The benefit is you could complete three times the area in about the same time.”

One of DroneSeed’s drones. The startup is currently working on technology to enable one operator to control multiple drones at once. Courtesy of Droneseed

But putting 15 drones in the air is complicated, a big reason why swarm drones are illegal without special permission.

“Swarm drones vs. flying one drone are essentially the same difference between running a couple miles on the treadmill at the gym vs. running a marathon, where you’ve got to make sure you have officials running a race, and you’ve brought your own Gatorade and glucose pack,” DroneSeed founder Grant Canary said.

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There’s the issue of the software for drones to communicate with each other. It also means having 15 times more batteries to charge, and hardware to inspect.

“Approval to operate multiple drones at once is a very complex exemption to get,” Skylogic Research founder Colin Snow said. “A lot of it has to do with where they are flying.”

“Thankfully we’re in a remote area right now and our space is clean,” Canary said. “If anything, we’re at an advantage. The FAA is happy we’re in a secluded, private place.”

DroneSeed’s drone fly over remote areas, primarily spraying herbicides. Courtesy of Droneseed

These drones also fly low to the ground—lower than even a helicopter—so there isn’t fear of collision with a manned aircraft.

“But I’m not sure with how many other applications this would apply,” Snow said. “I don’t see how this would work in any scenario outside of agriculture or sparsely populated areas.”

And even in remote areas, there are challenges, such as the concern of multiple, nonaffiliated drones buzzing around each other—an issue particularly relevant if drone package delivery becomes widespread.

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How do those drones communicate with other drones? What if another drone is flying an automated path to deliver a package and doesn’t notice the huge swarm in the way? The FAA is still exploring a system of air-traffic control for drones in partnership with NASA, but NASA won’t present its research on drone-traffic management to the FAA until 2019.

“Unmanned traffic management is a really long ways away,” said Jonathan Rupprecht, a lawyer focusing on drone issues. “Who is even going to pay for that?”

DroneSeed is obligated by the FAA to hand over their data so the government can use it in future rule-making that could legalize swarm drones. But for now, the rules are one operator, one drone.

“Personally, I think many operators can’t even handle one drone,” Snow said.