I think of the TSA as a failure more because of some of the controversies and failed policies. Overall, I think airport security is important and an organization like the TSA which oversees airport and transportaton security should have been created. The difference we see though are policies that are wasteful, invasive, or ineffective.

Plenty of people are able to board planes with banned items regularly, so obviously there's something not working properly. Likewise, I'm sure there can be an argument made that the lack of captured "terrorists" could be due to some of these deterrents in the airport and immigration? I don't know, nor do I have an answer. When it comes to these things, I tend to err to the government actually because they have the resources and people dedicated to studying these things. Too often though the wrong people are in charge and the goals are not implemented correctly.

I personally believe there's are more fundamental errors in airport security that has nothing to do whether or not it's the TSA or another organization.

Regardless, there have been shootings at airports (not by middle eastern terrorists either). Also if you go through security at any airports, you often find the same procedures used. It's not uniquely in US airports that they use pat-downs and body scanners. To be honest, I found at other airports you were able to get on planes with all kinds of shit they wouldn't allow at a US airport.

Air terrorism after 9/11 can be studied a variety of ways... I would think that international terrorists aren't as concerned with using planes as weapons because it's incredibly complicated, expensive, and just difficult. If you can get someone from one country to another without using planes, you can (quite literally) fly under the radar.

Terrorism in 2015 is certainly an issue internationally, only the methods are different than 14 years ago.