My point is that if improved airport security just shifts terrorist attacks to other places, the overall safety benefit is not as great as it may at first seem.
A plane hijacking can evidently cause enormous destruction with minimal equipment and personnel. Even just a bomb on a plane can easily kill 200-500 people depending on the plane’s capacity.
Ground-based attacks since 9/11 have been evidently less effective because a bunch of guys with guns attacking a train station or a rock concert can’t do as much damage as quickly as a hijacker essentially flying a cruise missile into a major office building.