Since this horse is just about beaten, I'll have one more go and then let it rest. When the subject is guns, the debate is difficult. Add in the specter of guns on aircraft and it gets worse. The anti-gun individuals have legitimate concerns and I value their debate, however:
The issue of "the pilots need to concentrate on flying the airplane" is a no brainer. We're pilots first and foremost. However, anyone who flies modern transport category aircraft knows that after the first ten thousand feet or so, who's flying the plane??? - the autopilot...right up until the last ten thousand or so before landing. Hell, half the time the crew's one wink short of napping - I doubt shooting a terrorist will interfere much with the autopilot .
"We should let the trained professional security screeners and air marshals handle security." - I absolutely, positively agree. However seeing that we live in the REAL world and cannot count on them to protect us ( LESS THAN 1% ON DOMESTIC FLIGHTS), I wish to have something to fall back on.
Is any security plan foolproof? Are guns the one and only answer? Of course not. Security, much like the safety of flight, is increased by adding layers of protection. The redundant systems and checklists we use everyday keep us safe in the air. A trained, able pilot with a firearm is another layer of security, to only act when all other layers have failed.
It is a gut-decision, but I refuse to be a victim. What did those brother of ours have to help them when the end was near? Security screeners? Air marshals? Nope. Passengers? Yes, finally, after the pilots were likely dead and word had spread as to their destination. I would hope to never have to use a firearm in the execution of my job, but if my job is to be the PILOT IN COMMAND, responsible for the ultimate safety of my ship, crew, and passengers, as well as those on the ground, I'd like to have a few more chips in my favor, and a few less for the bad guys.
Of, course, this is all mute so...whatever. Fly safe!