An airline employee stole a plane in Washington state and crashed in Puget Sound after being chased by F-15 fighter jets late Friday, but questions linger as to how he was able to do it and what security measures are in place to respond to these types of situations.

The employee of Horizon Air, a subsidiary of Alaska Airlines, took off from the Seattle-Tacoma International Airport at around 7:30 p.m. PT (10:30 p.m. ET) on Friday and crashed about an hour later, officials said. Sources identified the employee as Richard Russell and officials on Saturday expressed condolences to his family and loved ones.

The Alaska Horizon plane N449QX in a photo taken before the incident. Photo by J.K.

The employee had worked for Horizon Air for more than three years, and had undergone multiple criminal background checks, said Brad Tilden, the CEO of Alaska Air Group, in a Saturday press conference. Employees face background checks that go back 10 years, which they are required to renew every two years. Alaska Airlines and Horizon Air said they were not aware of anything popping up during this employee's background checks.

The Transportation Security Administration started running “real-time, recurring background checks for aviation workers, including airline workers” after an Atlanta baggage handler was discovered smuggling weapons in 2015. The airport also runs a check on individuals who have access to the runways and airplanes.

"The individual was fully credentialed. He had access to that area legitimately,” said Mike Ehl, director of operations at Seattle-Tacoma International Airport. “It’s inside the security fence so no security violations were committed."

Aviation security expert Jeff Price said that it is routine for ramp workers to have access to aircraft and that access is "part of their job." But he believes the worker who stole the plane must have had some level of training.

"It's a complex aircraft, it's a multi-engine aircraft, it's turboprop — this is not something you just jump in and figure out on the job," Price, a professor of aviation management at Metropolitan State University of Denver.

"And the maneuver that he pulled off — you really can’t just loop a plane and expect it to just work,” he said. "There’s some level of either flight experience of flight training there somewhere."

When the airport realized that the stolen plane was in the air, they ordered a ground stop and cleared the airspace, an order that ended at 8:40 p.m. local time, Ehl said Saturday. Due to the incident, 75 planes were delayed, nine flights were diverted and five were cancelled.

After the plane was stolen, the North American Aerospace Defense Command, also known as NORAD, scrambled two F-15 fighter jets. As of Saturday afternoon, officials said they do not believe that the jets were involved in the crash.

The Federal Aviation Administration reported that the airline employee had stolen a Bombardier Q-400 aircraft from the airport and asked the Department of Defense for assistance. NORAD then sent the jets from Portland to intercept the stolen plane.

This frame grab taken from footage filmed by bystander John Wauldron on Aug. 10, 2018 shows the airplane stolen from the Seattle-Tacoma airport, before crashing into the sparsely populated Ketron Island in the northwestern US state of Washington. John Wauldron / AFP - Getty Images

“The fighters were directed to fly supersonic to expedite the intercept,” NORAD said in a statement. “The stolen aircraft initially tracked south from Seattle-Tacoma. NORAD fighters were working to redirect the aircraft out over the Pacific Ocean when it crashed on the Southern tip of Ketron Island in the Southern end of Puget Sound. NORAD fighters did not fire upon the aircraft.”

NORAD said in a statement that they were prepared for these types of situations due to Operation NOBLE EAGLE (ONE). According to the Pentagon, ONE “is a direct response to the September 11, 2001, terrorist attacks at the World Trade Center in New York City and the Pentagon. It funds the continuing efforts to defend the United States from airborne attacks, maintain air sovereignty, and defend critical U.S. facilities from a potentially hostile threat.”

The United States budgeted $110 million in fiscal year 2017 for ONE, much of it going to the Army, though the Air Force controlled a sizable chunk of the budget — approximately $21.5 million — as well.

The program is supported by hundreds of national guardsmen and dozens of active-duty and reserve service members, which is the primary driver of cost. ONE also includes a large and maintained investment in air defense systems “to protect critical national assets, and to respond to National Special Security Events on a nation-wide basis,” according to a 2017 Pentagon report.

It appears that is one thing this unofficial pilot may have been concerned about.

According to audio recording captured between the pilot and the air traffic controller as the airline employee flew over Puget Sound, the pilot said that he was wary of returning to land because “they’ve probably got anti-aircraft.”

The air traffic controller seemed to laugh at that suggestion and said that was not the case.

The pilot said that he was wary of returning to land because “they’ve probably got anti-aircraft.”

In the end, however, the biggest issue that this pilot seemed to face is how quickly he burned through fuel. “I’m down to 2,100 [pounds of fuel],” he said. “I started at like 30-something.”

It appeared to come as a surprise to the former airline employee, who said he didn’t know how much fuel tended to burn on takeoff.

"It's burned quite a bit faster than I expected," he said.

The airline employee did not have a pilot's license, according to Gary Beck, the president and CEO of Horizon Air. Beck said they were investigating how the airline employee had learned to fly the plane.

Despite the security measures and the complexity of the airplane, the unnamed pilot still was able to steal an aircraft and take it on a joyride before his crash. It appears he had no greater reason than an unknown breaking point, according to the radio chatter with air traffic control.

"I've got a lot of people that care about me. It’s going to disappoint them to hear that I did this,” the man told air traffic controllers as he was flying the plane. “I would like to apologize to each and everyone one of them. Just a broken guy, got a few screws loose, I guess — never really knew it until now."

Price, the aviation security expert, said a worker stealing a plane is not something that aviation security measures are designed to address. Those ramp workers who have flight training typically want to become pilots someday, and stealing a plane would immediately end that career, he said.

“This is something that aviation security is not designed to prevent, it’s not designed to try and defend against, because it is such an anomaly that something like this occurs,” he said.

"We'll talk about what if a pilot does something, what if somebody on board were to do something, a flight attendant — that’s all covered within the airline security regulations and there’s procedures in place,” Price said.

"But for a procedure like this, the ramp workers, the mechanics, they have unfettered access to the plane," he said. "And it’s kind of a little bit of a leap to think, oh, what if one of them has some flight training and they’re going to jump in and just take off."

Price said that there should be an analysis to take a look at airlines’ workplace violence and mental instability indicator policies, like whether there are numbers other employees can call to report co-workers who may need help.

As more becomes known about the worker who stole the plane, the incident could provide valuable clues to the aviation security industry about what "pre-incident indicators" to look for, he said.

"There might need to be a procedure in place where if you’re not a pilot or a flight attendant, you’re not allowed on the plane unless there is someone there that is responsible for the aircraft," he said.

"But that’s going to have to be looked at and the operational impact, he said. “This just might be a complete, total anomaly."