@ stun guns of various types. These would have to be purchased and pilots trained in their use. Moreover, a pilot strapped into his seat might get off a pistol shot over his shoulder but would be hard-pressed to use a less accurate and shorter-ranged taser.
@ Sky marshals provide a level of security and deterrence, but there will never enough of them to put one or two on every flight. Even with sky marshals, terrorists can still take over a plane if they use a team of five or six determined men and have at least one firearm.
@ A volunteer militia or posse is an idea much beloved by the 2nd Amendment crowd. Under this theory, anyone who is an off-duty policeman, certain types of soldiers (those trained to use pistols), and perhaps those civilians with concealed carry permits (issued in 32 states) would (perhaps after a special training course) be allowed to carry a handgun on a plane (provided they agreed not to drink alcohol). While the thought of a hijacker being cut down by a dozen cowboys is amusing, the practicalities are impossible. Congress would never pass laws allowing this, and thousands of people who never worried about a terrorist might worry about the thought of a dozen pistols in semi-trained hands around the cabin. Liability issues alone would make the idea a legal nightmare. It would, however, certainly have a deterrent effect.
@ A variation of the sky posse idea would be to allow military personnel (mostly reservists, even State Guard troops) to take special courses and volunteer to (one day a month) ride on aircraft in uniform carrying a pistol. While there would not be enough for every flight (and volunteers for flights to Las Vegas might exceed the number of aircraft), the idea that a terrorist would not know until after he boarded a flight if an armed soldier would be added to the passengers might have a serious deterrent value.--Stephen V Cole
GUNS IN THE COCKPIT?- There is considerable debate over how to quickly improve the security of aircraft. The obvious things (strengthening the cockpit doors, improving security on the ramps) will take time. Pilots are actively debating measures that they can take immediately, the most controversial of which is to allow pilots to carry their own pistols. This could be implemented immediately (or in a couple of weeks if pilots were required to take the equivalent of a 'concealed handgun course', a month or two if they were required to take a new course on cockpit defense that someone would first have to invent.) The debate is furious. Pilots note that their only defense against the new "crash the plane" style of terrorism would be to make a radical maneuver and hope that the hijacker (standing in the door and not strapped into a seat) would be thrown to the floor and disabled. Such maneuvers are dangerous and could result in a crash in their own right. At least, so the theory goes, with their own pistol they could at least shoot an intruder and hope that the bullet didn't hit anything vital. Besides, the theory goes, don't Israeli pilots carry pistols? No, as a matter of policy, they do not. The cockpit door is reinforced and would take considerable time to break through, and one or more armed sky marshals is on every passenger flight by EL-AL (the Israeli airline). Pilots are told to land the plane as quickly as they can and let the sky marshals deal with the hijackers or die trying. Alternative ideas include: