My initial impression is to call "BS" on this.
I think the guy intentionally smuggled the weapon, which was not in plain sight, or had it passed to him at his destination specifically to mess with security and make a scene. Sort of like people at the casino where I worked deciding to plant false bombs so they could pretend to find them and then be "big heroes" for it, or just to try and make security look like a group of idiots, except in this case it appears he wasn't caught red handed doing it.
Simply put, if this did happen it's a sign that our security is not tight enough, probably due to all the complaints and the busy season. That or security is ironically treating Muslims with kid gloves stupidly enough. After all, this is all due to Muslim terrorists, but our domestic policies are such that singling Muslims out is wrong, so ironically with all the complaints I wouldn't be surprised if the group that should be being checked out the most intensely is being given a pass to "prove we aren't being discriminatory". It's possible that if this guy is a Muslim (and I'm guessing this is probably the case with a name like "Farid") his backround as a long time businessman might have convinced security to let him through unusually easy so they could point to him later and say "see we don't hassle all Muslims", except in this case it kind of backfired.
Still, just the fact that this made it into the media, and how idiotic it makes the system look, leads me to believe that it was set up intentionally. After all if *I* was in that position and got a gun through security accidently, the last thing I'd do is walk up and say "hey look, I got this gun through security".
If I was the guy in charge of this right now, I'd pull a "Judge Dredd", just because he admits to the crime doesn't mean it's not a crime. Time to invoke "The Patriot Act" bring him in for the most rigorous interrigation the law allows, in this country or an allied nation which is less picky (even if we're not supposed to do that) and get to the bottom of it. If it turns out that it's him trying to make a scene to undermine confidence in the system, we treat him like a terrorist, perhaps even going so far as to make it treason if he's a US citizen. If it's not, then he still brought a gun on a plane and we have a nice cell waiting for him for however many years in a regular prison it carries.
With a system this important, I think this guy did some damage by going public with it and speaking to the media. I believe strongly enough in this kind of security and the need for it at the moment that I think just letting this go is a bad move. To put it bluntly, if security fails, and someone points out a security failure which might encourage other people to exploit it, that's a problem.