(01-25) 10:41 PST NOVATO -- A Novato teenager has been arrested in Tennessee for allegedly plotting to hijack a plane from Los Angeles, authorities said Friday.
The 16-year-old was not identified because of his age. He was being held at Davidson County Juvenile Detention Center in Nashville, and a spokesman for the U.S. attorney's office in that city confirmed that the office is reviewing the case.
The boy was a passenger on Southwest Airlines Flight 284, which took off Tuesday from Los Angeles and landed in Nashville. He was found with handcuffs, duct tape and yarn in his bag, authorities said.
The teenager was calm during the flight and didn't make any attempt to hijack the aircraft, authorities said. But FBI spokesman George Bolds characterized the items as "suspicious" and said the boy had told FBI officials that he had planned to commandeer the aircraft.
The FBI also had said Thursday that a search of his home revealed a "mock cockpit." Nashville prosecutor Jon Seaborg said what was found in the home was "a photograph of the inside of a small aircraft, something you'd find in a bookstore."
Nashville-area prosecutors and court officials said the teen pleaded guilty Friday to a "delinquent act," but they refused to provide other details. A juvenile court judge ordered the boy sent back to California for disposition of that charge and other charges pending against him.
Novato police Sgt. Jay Demski said the boy's parents had reported him missing about 11:30 a.m. Tuesday.
"Subsequently, after his arrest in Nashville, we have been cooperating with Nashville airport police and the FBI," Demski said.
Chronicle staff writer Marisa Lagos contributed to this report.
Southwest airliner (file photo). 
A 16-year-old male from Novato, California has been arrested in Tennessee over allegations he intended to hijack a commercial passenger airliner in the United States. 

The boy, who was unnamed due to his age, was a passenger on board Southwest Airlines Flight 284 from Los Angeles to Nashville on Tuesday, with his parents reporting him missing at 11:30 am the same day. Although he remained calm throughout the flight and made no hijacking attempt, authorities report he had handcuffs, duct tape and yarn inside the aircraft cabin with him. Although his arrest was only made public on Friday, it is reported that he was detained immediately on reaching Nashville International Airport.

George Bolds, a spokesman for the Federal Bureau of Investigation (FBI) said that the items were "suspicious" and that the boy had informed the FBI he had indeed intended to hijack the aircraft. An FBI agent told reporters that he felt the plot was ill-conceived, saying "His plan had a low probability of success."

The FBI also conducted a search of his home on Thursday, finding in his room "a photograph of the inside of a small aircraft, something you'd find in a bookstore."

Subsequent to his arrest he pled guilty on Friday to a "delinquent act," according to local officials. A juvenile court judge ordered him to be returned to California for continued perusal of that charge as well as others set to be made. He is currently in Davidson County Juvenile Detention Center in Nashville.

Authorities believe that the teen was suicidal, but the FBI dismissed earlier reports alleging that he intended to crash the airliner into a Hannah Montana concert in Lafayette, Louisiana.