In the knee jerk responses we have seen so far, it is absolutely true that we are doing the terrorist's work for him in taking away our own freedoms and destroying our own economies and way of life in the guise of increasing 'security'. In a world that is lead by the truly stupid, what else can we expect?
In blaming every other country, including the UK and Canada for their own failings, the US risks destroying the relationships forged in blood.
Many countries categorise the PIC as a "special constable" and as part of maritime tradition he has a responsibility to his crew and passengers. If this means he must be armed, then that is the end of the discussion. If he does not want to be armed when that is a requirement for the job, let him get a new job.
Put a secure electronic lock on the flight deck door, operated by a four digit code set by the PIC before every flight. He can give the code to the purser or not, as company policy dictates. He can still open it from his seat as before, so if the cabin crew want access they can call ahead. But no-one gets into the cabin unless he allows it. He should also have a panic button which will put a solid lock on the door, so that it cannot be kicked in or forced (maybe a stronger door needed, with no blowout panels or smaller ones). In an emergency he can set this lock, which cannot be released in flight. No matter the threats, he will not be able to open the door.
This would solve the problem we saw in this attack, but make other attacks harder to combat. Is it what we want?