The man was chased by police and TSA officers, and was captured on a plane, said Perry Cooper, a spokesman for Sea-Tac Airport. The incident started about 11:30 pm ET, when the man sprinted by the security checkpoint at concourse D, Cooper said.
He bolted out of a door and made his way out on the tarmac. He broke a window, by punching it, and was able to get into an empty American Airlines plane, Cooper said.
Representatives from American Airlines could not be immediately reached for comment.
The man, described as in his 20s, was apprehended on the plane.
Nobody was hurt and no flights were delayed. The suspect will be taken to jail, Cooper said.
The incident may have been influenced by drugs, Cooper said.