At the airport here in CT., the CT State Police are in charge of patrolling the airport. I don't travel often, but when I have, I haven't seen an overwhelming number of Troopers. Sadly, in the vast majority of airports that I've been to, there really isn't that much, security, if any at all, until you actually get to the TSA check in, where you have to take off your shoes, your carry on gets x-ray'd, etc. So, just like in the case here, anyone can walk in, just like this guy, with a hidden weapon, and start shooting, bring in a bomb, etc.
Perhaps, and I'm sure it'll happen, eventually, we'll see the security start before you even get to walk into the airport itself. Of course, given the fact that you have to arrive 2 hrs early as it is, IF something were to change, well, expect much longer delays.
I might have asked this before, but I'll ask again. I'd be interested in knowing how airports in various countries, that tend to have more of a terror potential, ie: Israel, deal with things like this? I know people are always complaining because they feel we are living in a 'Police state" but you can't have your cake and eat it too. I mean, if you're worried about stuff like this happening, then don't complain when you're greeted with guys with machine guns.
*edit* Just to clarify, when I said *you're* I wasn't talking about YOU personally, just making a general reference.