Bruce Schneier gives a cogent opinion:
Exactly two things have made airplane travel safer since 9/11: reinforcing the cockpit door, and convincing passengers they need to fight back. Everything else has been a waste of money. Add screening of checked bags and airport workers and we’re done. Take all the rest of the money and spend it on investigation and intelligence.
This is exactly right, though it clearly elides the cesspool that our investigation and intelligence apparatus currently is, a critical problem that the government shows zero interest in taking on.
The 9/11 Commission pointed it out and the reaction has been to add another layer or two of middle managers and most definitely not to drain the swamp and rebuild a reactive and reasonably transparent national intelligence apparatus. Easier just to scan our junk, I guess. Kick all other cans down the road and then roundly blame the other party when the next big (but plainly avoidable) intelligence failure happens.
Lemkin 