Military jets were scrambled late Friday evening after a ground service agent at Seattle's Sea-Tac Airport stole a plane and performed air stunts in the sky before crashing about an hour later on a sparsely populated island near the city, officials said.

No passengers or crew were on board the plane. The Pierce County Sheriff's Department on Friday night described the pilot as a 29-year-old "suicidal male." The person who stole the plane died, Alaska Air Group CEO Brad Tilden said Saturday, and he said the entire company extends its sympathy to the man’s family, loved ones and co-workers.

Sheriff Paul A. Pastor said there was no indication that this was a terrorist attack or that the man wanted to hurt anyone else, and said the man had performed "air stunts."

"Most terrorists don’t do loops over the water," he said at a news conference Friday.

The small passenger plane was taken from a maintenance position at around 8 p.m. local time (11 p.m. ET) and was not scheduled for a passenger flight, according to Alaska Airlines.

The airline said the man worked as a ground service agent for Horizon Air, whose plane he stole. Horizon Air is part of Alaska Air Group and flies shorter routes throughout the U.S. West.

The plane later crashed in a wooded area on Ketron Island in rural Pierce County, causing a fire. No ground structures were involved in the crash site, according to the airline.

Two F-15 jets were scrambled out of Portland, Oregon and attempted to redirect the aircraft out over the Pacific Ocean when it crashed, the North American Aerospace Defense Command (NORAD) said on Twitter. The fighters did not fire upon the aircraft, it said.

"I appreciate the quick reaction and professionalism of our Airmen and the entire NORAD team who were on alert today, as they are every day of the year," said General Terrence O'Shaughnessy, commander of North American Aerospace Defense Command.

Broadcastify audio recordings appeared to capture the desperate pilot speaking to air traffic control operators as he flew over Puget Sound.

An airline employee conducted an unauthorized takeoff without passengers at Sea-Tac; aircraft has crashed in south Puget Sound. Normal operations at Sea-Tac Airport have resumed. — Sea-Tac Airport (@SeaTacAirport) August 11, 2018

"I've got a lot of people that care about me. It's going to disappoint them to hear that I did this. I would like to apologize to each and every one of them," the man said over the radio system.

An air traffic control operator could be heard trying to convince the man to land the plane.

"We're trying to find a place for you to land safely," the operator said.

"Yeah, not quite ready to bring it down just yet," the man responded.

NBC News could not verify the recordings.

Pastor said he did not believe there were any other injuries or casualties in the crash. The fire was contained, and the West Pierce Fire & Rescue said they would remain on the scene on Saturday to mop up hot spots.

The incident temporarily kept planes stranded on the tarmac at Sea-Tac and passengers waiting on board their aircraft after landing.

Quincy Carr, who was flying in to town to perform on a Norwegian cruise line ship, said the pilot told passengers on his plane that there was an incident and they were stuck on the tarmac for about an hour.

"I felt like we were on the ground and we were safe, we weren’t in the sky while something was going on," he said. "So it really wasn’t that bad — to me,” Carr told a reporter from NBC affiliate KING5 of Seattle at after getting off the plane.

"But I do know there were people on the plane that were kind of panicked," he said.

Another passenger flying in from Philadelphia told the station that travelers were grounded on his flight for about 40 minutes before they were allowed to leave.

The crew on that plane said there was some kind of emergency on the runway but did not tell passengers that a plane had been stolen, he said.

We are aware of an incident involving an unauthorized take-off of a Horizon Air Q400. We believe there are no passengers on board. More information as we learn more. — Alaska Airlines (@AlaskaAir) August 11, 2018

"Of course, everyone’s pulling out their phone and finding out what’s going on, and seeing this crazy story," he said.

Sea-Tac Airport said normal operations have since resumed.

"Our hearts are with the families of the individual aboard as well as all of our Alaska Air and Horizon Air employees,” Horizon Air chief operating officer Constance von Muehlen said in a statement.