Reports of jetliner encounters and other drone-safety episodes in the U.S. have fallen over the past two years, possibly because of software improvements and efforts to educate users about proper use of the consumer devices.

There were 1,633 drone-safety reports in 2020, the lowest total in five years, according to Federal Aviation Administration data.

At least part of that decrease was likely a consequence of the coronavirus pandemic and the drop in flying overall last year, but the trend of fewer drone incidents began when air traffic was robust in 2019. The 2,152 reports that year were 6.7 per cent lower than in 2018, according to the data.

The reasons for the decline aren’t entirely clear, but it came after years of attempts to better inform drone operators and followed several highly publicized episodes near major airports. The world’s largest drone manufacturer also made significant improvements in its safety software just before the trend began.

“I think it’s a combination of all those things,” said John Hansman, a professor at the Massachusetts Institute of Technology who has studied drones.

Drones were initially a fad that drew thousands of people without any interest in the rules of aviation, said Tyler Dobbs, director of government affairs for the hobby group Academy of Model Aeronautics. In recent years, many of those users have fallen away, leaving a core group more committed to heeding drone education campaigns, Dobbs said.

“We do feel like that message is getting out more and more,” he said.

SZ DJI Technology Co., which sells the vast majority of drones in the U.S., revamped its software in the fall of 2018 to expand no-fly zones near airport runways, where many incidents occur.

“It would make sense that making that change to the drones would have a corresponding impact on the sightings that would happen in 2019 and beyond,” said Brendan Schulman, a vice president at the company.

The FAA declined to comment on the decrease. Almost all of the reports are eyewitness accounts that have proved impossible to verify. The agency continues to work on multiple efforts to educate the public and work with law enforcement agencies on the issue, it said in a statement.

Even with the decrease, the FAA records contain scores of cases.

Just last December, there were reports of drones hovering over a prison near Omaha, Nebraska, and above Dobbins Air Reserve Base in Marietta, Georgia. Los Angeles International Airport had to briefly halt one runway’s departures on Dec. 19 after pilots on two consecutive flights reported seeing a drone.

In addition to hobbyists, increasing numbers of commercial drones are being used for such things as photography, inspections and mapping. While federal rules don’t yet allow it, companies including Amazon.com Inc. and Alphabet Inc.’s Wing are testing autonomous delivery drones.