North Dakota prohibits mounting lethal weapons on drones. Arkansas won’t allow remote-controlled aircraft to photograph critical buildings such as power plants and oil refineries. Michigan bans using drones for hunting — or to harass hunters.

And North Carolina requires commercial drone operators to take a test to ensure they’re familiar with the rules of the road.

These are among state- and city-level laws adopted – among hundreds of more bills proposed – to regulate the fast-growing world of drones. But these local laws are on a collision course with the Federal Aviation Administration, which contends it controls the airspace and wants to set a single national policy for drones instead of a  patchwork of local laws.

FAA’s authority over airspace is unquestioned for safety issues such as keeping drones lower than 400 feet or away from airports, said Troy Rule, an associate professor of law at Arizona State University. Whether that authority extends to issues like privacy is a matter of debate, he said.

“It depends who you ask and it’s not very clear at all,” Rule said. “It would need to be litigated.”

The FAA’s authority over safety “still leaves a lot of room for states to act, and they have,” said Stephen Martinko, a former transportation staff member in Congress who is now a government affairs counselor at K&L Gates LLP. “When you start doing that, it gets very complicated and very confusing.”

Congress ordered FAA in 2012 to develop rules governing how drones would share the sky with passenger planes. The first regulation for commercial drones weighing up to 55 pounds is expected in June. The FAA in December published a seven-page statement asserting its congressional authority to regulate use, management and efficiency of the national airspace.

A U.S. Senate bill introduced Wednesday would restate that supremacy of federal law over state and local laws dealing with the design, manufacture, testing, licensing, registration, certification, operation or maintenance of drones. A committee vote is scheduled Wednesday on the bill.

The Senate measure would explicitly give FAA supremacy over all drones laws, Rule said. That would give companies like Amazon, Google and Walmart a one-stop shop for their drone-delivery proposals. But that would also  block local governments  from adopting measures prohibiting encroachment on private property similar to zoning laws, he said.

“This is arguably one of the largest property-rights grabs by Congress in history,” Rule said.

National groups are debating whether it’s better to have a single federal law or a variety of local laws.

“The FAA’s message is clear,” Brian Wynne, CEO of the Association for Unmanned Vehicle Systems International, told a Senate panel Thursday. “State proposals have the potential to create a complicated patchwork of laws that may erode, rather than enhance, safety.”

Brendan Schulman, vice president for policy at DJI, one of the largest drone manufacturers, urged national standards to teach the rules of the road. .

If cities, states and the federal government each adopt different rules, “I think it’s going to be chaos,” Schulman said.

But Jay Stanley, senior policy analyst for the American Civil Liberties Union, said a variety of local laws might not be so bad. He compared drone policies to other quality-of-life issues about noise and safety and privacy, dealt with through local legislation for leaf-blowers or handguns.

“It will be a patchwork,” Stanley said. “This is a complex, sausage-making process in place.”

In 2015, 45 states debated 168 bills around drones, according to the National Council of State Legislatures. Twenty states passed least 26 pieces of legislation, the group said.

Michigan, for example, approved a pair of laws banning drones for hunting or to harass hunters.

“These laws help protect the integrity of the sport,” said state Sen. Phil Pavlov, R-St. Clair Township.

The debate has been rocky in spots.

Complaints poured in from photographers, news stations and agricultural interests after Arkansas state Rep. Justin Harris, R-West Fork, introduced legislation to outlaw drones photographing private property..

“I thought the sky was falling,” Harris said.

Harris ultimately won approval of the law by fitting it under an anti-voyeurism statute, to prohibit filming someone in their backyard or through a window from a drone.

“This was important for a particular segment of the population of women who may be in hiding in an abusive situation,” Harris said.

Another Arkansas law approved last year prohibited using drones to photograph or electronically surveil potential terrorist targets such as power plants or oil refineries.

State Rep. Matthew Shepherd, R-El Dorado, said the chemical industry asked him to sponsor the legislation after a measure dealing with broader privacy concerns was defeated.

“They obviously need to be secure,” Shepherd said. “It’s an area of law that at least at this point, the development of it is going to be primarily at the state level.”

In North Dakota, state Rep. Rick Becker, R-Bismarck, proposed one of the first drone bills in the country in 2013, to require police to have a warrant if they use the aircraft for surveillance. The bill failed. When he revived it in 2015, the legislation became law with an additional provision to ban lethal weapons on drones. That was taken to allow law enforcement to mount non-lethal weapons such as tasers, although local police say they haven’t done yet, he said.

“I don’t think we have to worry about it being confusing,” said Becker, who plans legislation in 2017 to ban all weapons on drones. “If we can figure out the difference in speed limits and the fines for speeding in different states, we’ll do just fine with differences in drone legislation.”

North Carolina began in January requiring commercial drone operators to pass a test and obtain a permit from the division of aviation before flying. The state has issued 108 permits this year through March 10, according to Chris Gibson, the drone-program manager for the state’s division of aviation.

The test requires familiarity with state laws prohibiting weapons on drones, getting permission from property owners to launch and recover drones, and dealing with privacy, to prevent taking pictures of people on private property without their permission, Gibson said.

“We were very careful to not do anything to regulate airspace or how these things can operate in the airspace,” Gibson said. “It’s really geared toward regulating how they are interacting with persons and property on the ground in North Carolina.”