The biggest surprise may have been that Richard Russell, the man who stole the plane and died in the crash, was a member of the ground crew at Sea-Tac, not a pilot.
He used a vehicle known as a pushback tractor to move the empty turboprop plane and took off without authorization at 7:32 p.m. Friday, officials said.
Two F-15 fighter jets were scrambled as "Rich" flew the passenger plane in an aerial loop, then headed south.
Late last night, a mechanic working at the Seattle-Tacoma airport, made a decision to literally steal a passenger plane.
His former coach said there's still a weight belt in the Wasilla High gym that says "Beebo" - adding he was in "total shock" over the incident.
The airport ground service agent also apologised to his friends and family, calling himself a "broken guy".
"The responding fighter pilots flew alongside the aircraft and were ready to do whatever was needed to protect us, but in the end the man flying the stolen plane crashed", Inslee said.
Seattle FBI agent in charge Jay Tabb Jr. cautioned that the investigation would take a lot of time, and details, including the employee's name, would not be released right away. "If they want to cover up the issue they can usually do so if they try", Prof Bamber said.
Pierce County Sheriff's spokesman Ed Troyer told the Bellingham Herald that information was preliminary regarding the developing incident.
"We at Quiet Skies Puget Sound are deeply saddened by the frightful tragedy that occurred Friday evening with the unlawful use of a Horizon Air Q400". There were no passengers aboard. "Our hearts are with the family of the individual aboard as well as all of our Alaska Air and Horizon Air employees". His job included directing aircraft for takeoff and gate approach, handling baggage and tidying and de-icing planes.
Southers, the aviation security expert, said the man could have caused mass destruction. "Pilots kept plane out of harm's way and people on ground safe", the sheriff said on Twitter. "We don't know how he learned to do that", he said.
Witnesses reported seeing the plane being chased by military aircraft before it crashed on Ketron Island, southwest of Tacoma, Washington.
"The people that do that typically have one of them in the cockpit and one of them in the tug, towing the airplane", he said.
"We're working to find out everything we possibly can about what happened", Brad Tilden, chief executive of Alaska Air Group, said in a statement.