US man steals Seattle plane in airspace terror

There has been a major security incident in the US after a plane was reportedly stolen from a Seattle airport.

Local media reports say the aircraft was stolen by a ground employee and took off without authorisation. There were no passengers on board.

"An airline employee conducted an unauthorized takeoff without passengers at Sea-Tac; aircraft has crashed in south Puget Sound," Sea-Tac Airport tweeted.

Twitter posts say the aircraft was being followed by Air Force fighter jets and appeared to either crash or be shot down. Photos have been posted showing a plume of smoke.

"Witnesses saw plane chased by F-15s, then a boom, and smoke," a local reporter tweeted.

Transcripts have been posted online showing the air traffic controller attempting to talk the pilot into landing.