It turns out Smith shouted out "bomb" in the airport, which is what led to his arrest:
LA Airport police detained 49ers LB Aldon Smith after he indicated he possessed a bomb, per public LA policeinformation officer Karla Ortiz.— Adam Schefter (@AdamSchefter) April 13, 2014
Seeing multiple alleged eye-witness tweets reporting #49ers OLB Aldon Smith being arrested at LAX.— Luke Easterling (@NFLDraftReport) April 13, 2014
Just saw Aldon Smith of 49ers get arrested at LAX. He was not happy. Don't know what happened to precipitate it. @espn— John Egan (@JohnJEgan) April 13, 2014
Seems like something that could have just been made up for attention, but Smith did tweet this out Sunday morning:
It was worth it! It was all worth it!!!— Aldon Smith (@AldonSmith) April 13, 2014
That tweet did come several hours before this news of an arrest though, so it's unclear if it's related or just coincidence, but it's looking like they may indeed be related:
It's safe to say Smith was involved in some kind of incident, though the severity of it is unknown, and it doesn't appear to have been something too serious.
It's going to be big news only because of Smith's past transgressions.
He missed five games last season while being treated for substance abuse. He is also facing felony gun charges and a charge from a DUI arrest, his second season entering the NFL.