Remember when they gave pilots guns to increase airplane security? On Saturday, a US Airways pilot accidentally fired his gun in the cockpit while trying to stow it, blowing a hole in the plane. Security expert Peter Biddle uses this as an object lesson to explain why "trust isn't transitive."
Let's look at this quote from the article in question, attributed to Mike Boyd: "if somebody who has the ability to fly a 747 across the Pacific wants a gun, you give it to them." This is a horribly flawed assumption, because it assumes that trust is transitive, when clearly it isn't.
The reason trust isn't transitive is because trust is most often based on data regarding the past which allows us to make assumptions about specific competence, quality of performance, and behaviors in the future.
We can assume that a trained pilot, when facing piloty thingies, will act like a trained pilot. WE CANNOT ASSUME THAT A TRAINED PILOT WILL ACT LIKE A TRAINED LION-TAMER WHEN FACING A WILD LION.
Skills from one domain cannot simply be moved from that domain to another. Saliently, the pilot in question must have thousands of hours of flight time, has done the pre-flight check hundreds or even thousands of times, has been steeped in pilot-ness and thus pilot-safety, probably since he was a late teen. He's very likely an extraordinarily safe pilot. We can assume that every experienced 747 pilot has a keen awareness of the potential lethality of full loaded 747. In the past we can assume that they at least had a deep appreciation of the potential for harm to their own passengers, and post 9/11 we can assume that they appreciate the harm their plane can be to thousands of additional people.