Seattle aeroplane theft: Fighter jets 'used sonic boom' to intercept Alaska Airlines plane

Two 15-Cs broke the sound barrier to intercept the stolen Alaska Airlines plane that was stolen from Seattle-Tacoma International Airport on Friday night.

Facebook users reported hearing sonic booms over Eatonville.

Earlier, a "suicidal" airline mechanic stole an empty Alaska Airlines plane and took off from Sea-Tac International Airport in Washington state before crashing near a small island, officials said.

Preliminary information suggests that the 29-year-old mechanic stole the Horizon Air Q400 and the crash occurred because the person was "doing stunts in air or lack of flying skills," the Pierce County Sheriff's Department said.

Witnesses reported seeing the plane being chased by military aircraft before it crashed near Ketron Island, southwest of Tacoma, Washington.

There were no passengers aboard.

Ed Troyer, a spokesman for the Pierce County Sheriff's Department, said on Twitter that the man was suicidal and there was no connection to terrorism.

The sheriff's department said they were working to conduct a background investigation on the man, whose name was not immediately released.

The man could be heard on audio recordings telling air traffic controllers that he is "just a broken guy."

The US Coast Guard was sending a 45-foot (14-metre) vessel to the crash scene after witnesses reported seeing a large plume of smoke in the air, Petty Officer Ali Flockerzi said.

Horizon Air is part of Alaska Air Group and flies shorter routes throughout the US West.

The Q400 ix a turboprop aircraft with 76 seats.

Spokesmen for the Transportation Security Administration, the US Department of Homeland Security and the Federal Aviation Administration directed inquiries to local authorities.