Airport screening was introduced in the US in 1973. In the 5 years prior to this there was 12 major aircraft hijackings originating from the US. In the 5 years

Airport screening was introduced in the US in 1973. In the 5 years prior to this there was 12 major aircraft hijackings originating from the US. In the 5 years after this, there were 2. Airport screening effectively ended the very rapidly increasing number of aircraft hijackings which occurred in the early '70s. There were of course other factors in play, but the sharp drop (1972 saw 6 major hijackings) after the introduction of airport screening is certainly a good indicator of the effectiveness of airport screening. Airport screening isn't completely effective, but it's fairly demonstrable that having a layer of security when boarding an aircraft does act as a deterrent to aircraft hijackings. It doesn't completely stop them, but it does make a difference. I'm not going to defend the TSA as an organisation, but to say that airport screening as a whole serves no purpose is not really based in fact. It's almost certainly possible to bring banned items onto aircraft, and it's fairly reasonable to assume that if someone is dedicated enough they will find a way to cause death, but what airport screening does do is act as enough of a deterrent that aircraft hijacking isn't seen as an easy crime. The rapid drop in numbers post-screening shows that.