Argument: Gun-training for pilots would be easy; they face a simple scenario
Dave Kopel & David Petteys. "Air Neglect". National Review Online. July 2, 2003 - It should be remembered that an armed pilot resisting a hijacking faces a much simpler scenario than a typical defensive shooting by an FBI agent, a police officer, or a citizen with a concealed handgun permit. These latter three must be prepared for surprise attacks, and for the possibility of using firearms in any of the hundreds of places where a person might be during the course of a day. Law-enforcement officers must confront the additional difficulty of being forced to intervene in situations (such as domestic disturbance) in which it may not be immediately clear who is the aggressor and who is the victim.
In contrast, the armed pilots would only use firearms in a place they know extremely well: their own cockpit. Because cockpit doors are now secure and barricaded, and because of enhanced communication abilities between the cabin stewardesses (or stewards) and the cockpit, pilots would likely have warning before a hijacker breached the cockpit door. The attacker would be a very few feet away-as opposed to attackers who might be many yards away in ordinary ground-based defensive gun use. Unlike in ground-based defensive gun use, the pilot would not have to worry about whether use of deadly force should be delayed in the hopes that lesser force or a warning might suffice; a hijacking scenario and cockpit invasion would by definition require use of deadly force.
In short, there is no good justification for TSA inventing a requirement for a $12,000 federal training course, and using this pretext as a choke point to prevent arming pilots.