How did an aircraft thief take off without a license or clearance? Here's what experts believe.

Experts are trying to determine exactly how a baggage handler was able to hijack an empty Alaska Airlines plane from a Seattle airport and perform advanced stunt maneuvers before crashing to his death.

The first part was as simple as climbing into the cockpit and flicking a switch. The spectacle that followed was another story.

“They don’t necessarily use a key so there’s a switch that they use to start the aircraft,” National Transportation Safety Board official Debra Eckrote said Saturday as she spoke with media about the theft of Horizon Air Q400.

The thief was able to taxi the plane down the runway and take off without clearance from air traffic controllers.

Richard Russell, a 29-year-old Horizon Air employee, was reportedly "suicidal" and decided to hijack the 76-seat plane around 8 p.m. Friday from a maintenance area of the Seattle-Tacoma International Airport in Washington, according to reports. Russell then flew the aircraft on a 90-minute joyride before crashing it into a remote island.

How did he fly the aircraft?

Russell had a security clearance that allowed him access to the planes, but lacked a license to fly it.

“He did say he spent a lot of time with video games,” said Mark Rosenker, a former chairman of the NTSB, told CBS News. “There are video games that deal with a simulation of this aircraft. And the fidelity is amazing. You could learn a great deal from playing these types of games.”

Witnesses filmed the plane performing barrel rolls and loop-the-loops during a 90-minute joyride. Military planes pursued the plane, chasing it away from highly populated areas. The plan flew toward Ketron Island where it crashed into a ball of fire, reports state. At one point, he flew the plane upside-down.

"He did some aerobatics in the airplane that I was shocked to see," Rick Christenson, a retired operational supervisor for Horizon Air, told the Daily Mail.

Paul Pastor, Pierce County sheriff, said there was no indication that the intent was to harm others.

“Our information now is there was only one person on the plane. I understand the person may have been doing some air stunts or whatever. Some aircraft were scrambled from the Air Force base. There was no indication this person flying the plane was trying to damage anything," he said.

What did family members and friends say?

Russell’s family said Saturday they were stunned and heartbroken at his actions, the Daily Mail reported.

At a news conference, friends read a statement by family members that said Russell was a faithful husband to his wife, Hannah, and a good friend who was “loved by everyone.”

“It may seem difficult for those watching at home to believe, but Beebo was a warm, compassionate man,” they wrote. "Beebo" was Russell's nickname.

The family also said their faith is helping them deal with the loss.

“We are devastated by these events and Jesus is truly the only one holding this family together right now,” the family said.