A little more capability to attack requires an immense amount of additional capability to defend against. I think that depends on the type of weapon. Part of

A little more capability to attack requires an immense amount of additional capability to defend against. I think that depends on the type of weapon. Part of the issue with airlines is how highly valued human life is. If for example all we were trying to do is have an acceptable level of losses on drone aircraft we'd probably accept a much lower level of protection (and correspondingly lower costs)>