FAIRBURY - The Federal Aviation Administration is working with state and local authorities to determine who's behind a series of mysterious nighttime drone flights over northeastern Colorado, western Nebraska, and now, parts of central and eastern Nebraska.

The first sightings occurred on Dec. 28. It took less than a week for those sightings to make their way to southeast Nebraska.

Residents of Fairbury and Jefferson County have reported seeing large, fixed wing, military-style drones. The first reported sightings were on Jan. 3, with several more on Jan. 4-5. 

Jefferson and Saline County Emergency Manager John McKee says there have been anywhere from 10-15 of these aircraft spotted per night in the Fairbury area between Jan. 3-5.

"There could be more or less," McKee said. "With them flying in the patterns and formations that they are, it's kind of hard to get an accurate count of all of those spread across the area."

Shalanna Ekis of Fairbury reported seeing drones on Sunday night around 5:30 p.m. near Gilead and Hubbell in Thayer County. She then reported seeing another in Crystal Springs Park in Fairbury around 8 p.m. Sunday, and one near her home around the same time.

There's also been reported sightings near Jansen, Harbine, Diller and Hebron since Sunday. There were some reported sightings in the Exeter, Strang and Dorchester areas on Monday evening.

Judd Stewart, a volunteer firefighter with the Fairbury Rural Fire Department, is a registered drone pilot for Jefferson and Saline County Emergency Management.

In 2019, Jefferson and Saline County began using three, quad-propeller drones to assist local law enforcement with emergency responses, like a missing person or a large fire. These drones are allowed to fly at night, per waivers from the FAA.

Stewart says the drones that he and his son Riley spotted near their property on Saturday night (Jan. 4) were nothing like the ones being used by local officials.

"You could tell they were (flying) lower, because we had low cloud cover and they were below the clouds," Stewart described. "We'd see them flying in a straight line and then they'd just disappear. A few minutes later, another one would appear in a different area. My son was able to get a good vision on one through binoculars, and he was able to identify the lights on the side and the strobe light in the middle. Just don't see that every day."

A Colorado sheriff hosted a closed-door meeting with law enforcement agencies and government officials Monday to talk about the recent rural sightings.

The drones reportedly have six-foot wingspans and fly in grid-like patterns hundreds of feet in the air in groups of 6-10. Law enforcement in Grand Island and Hastings also spotted these drones on Sunday evening.

The FAA says it's taking the sightings seriously and working to find out who's operating the devices and why. Sheriff's officials say it appears that no laws are being broken.

"At this point, I don't see that there's any need to get excited," McKee said. "Curiosity gets to us, and we wonder why they're doing that. Who knows if we'll find out? Hopefully, it's for the good. If they're doing training or whatever, hopefully it's benefitting someone someplace."

McKee, and other local law enforcement, want to remind the public that it is highly illegal to shoot any drones down.

"Any drone that is registered with the FAA is federal property," McKee said. "It'd be no different than shooting a plane. You'd do time. It wouldn't be pretty."

University of Nebraska drone journalism professor Matt Waite believes the drones are either military, or are being used for oil and gas exploration.

People can fill out waivers to fly drones at night, but, according to Waite, waivers are very rare.

"If someone is following the rules and doing this, then they had to have applied for an exception for this to that rule," Waite told news partner 10/11 NOW.

You can follow Tommy on Twitter @Tommy_NCN.