Security is now a multi $billion industry and the vast majority aimed at Aviation.
i live in London and use the London Tube system. Thousands pile onto the tubes, People from all walks of life and every nationality and religious back grounds.
whats more they drag cases and bags cramming themselves into packed tube trains which equally carry as many passengers as an Airline.
Who ever stops me dragging my case and checks my case through scanning machines or asks me to step through metal detectors?
No one!
so what makes aircraft so unique or attractive to terrorists especially as now they are such a hard target