I haver said it before but please let me repeat it for the benefit of this thread: Outside of the Air Marshalls there are already about two dozen agencies of all level s (including FBI, CIA, DEA but also Customs and Postal Inspectors and many others) that already are allowed to carry concealed, armed weapons about commercial aircraft *and they do*! For the purpose of avoiding firearms aboard an aircraft, not arming the pilots makes no sense at all.
I am personally very much in favor of arming those pilots who want to be armed. I am further willing to extend this right to any citizen of good standing who is not by law prohibited to own a firearm. What the chief pilot at UA thinks about it is good only in terms of corporate policy but not much else. Sort of like the Pope preaching about birth control.