According to Sgt. Karla Ortiz, the 24-year-old from San Jose was going through Terminal 1 screening when he made a comment indicating that he was in possession of a bomb.
Sgt. Ortiz says LA police made contact with him at the gate area where he became uncooperative. He was taken into custody and transported to LAPD-Pacific division where he was booked for false report of a bomb threat.
"We are disappointed to learn of the incident today involving Aldon Smith," 49ers general manager Trent Baalke said in a statement. "As this is a pending legal matter and we are still gathering the pertinent facts, we will have no further comment."
Last year, Smith was arrested for suspicion of driving under the influence after investigators say he crashed his car into a tree in a San Jose neighborhood.
Smith also last year pleaded not guilty to owning three assault weapons that are illegal in California in a case stemming from a 2012 incident.
Officials say Smith was released from jail at about 7:30 p.m. Sunday after posting $20,000 bail.