I really wonder why this hasn't happened yet. I can only assume that either terrorists are maniacally fixated on the airplanes, or there are approximately zero intelligent terrorists.
I don't consider it a particularly sophisticated attack, but it was undeniably effective both at injuring people and at spreading FUD.
Aircraft are an attractive target if you can cause the aircraft to crash, but most terrorist attacks on aircraft don't have that result.
> and at spreading FUD
Watertown residents' cars are no longer universally decorated with "W Strong" stickers. The feds had to strain mightily at the jury pool to get jurors willing to consider the death penalty -- sentiment in Massachusetts was 2:1 in favor of having Tsarnaev rot in prison.
Insofar as the Tsarnaevs had a political goal, I don't think they achieved it.
That is the problem with terrorism.
Sure, but the places where it happens anything that could even remotely be described as fairly regularly in parts of the world where the social and economic conditions and legitimate political outlets for dissatisfaction with those conditions are all vastly different than in the part of the world that has the TSA doing screening at airports, i.e., the US.
While it has happened at times in the US (e.g., Boston Marathon), it doesn't happen enough that the expected number of times it would be expected to have happened in airport lines if such events were even distributed among similarly-sized crowds would be anywhere close to 1.
So while clearly its not full of mass murderers, there are enough to cause chaos.