Smith was booked for investigation of making a false bomb threat. FBI spokeswoman Laura Eimiller said anyone who makes a bomb threat at an airport is potentially subject to federal charges, although no such charges have been filed against Smith.

A message seeking comment from Smith's agent wasn't immediately returned.

With the arrest, Smith is involved in three pending criminal cases.

"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."

A fearsome pass-rushing specialist, Smith took a five-game leave of absence from the 49ers last season to undergo treatment for substance abuse. He rejoined the team Nov. 5.