That happened, and it opened the eyes of MOST pilots to the real
possibility of unknown dangers at the airport. Plus, the DHS has
specifically warned us of threats possibly using GA aircraft in
terrorist operations. Accurate, overstated, or otherwise, I see that
as a "hint."

Let's say (for the sake of argument) that there really is some danger of
terrorists using GA aircraft for their nefarious ends. I still fail to see
any real benefit in carrying a loaded firearm to the airport. The chances
of me hurting myself or some innocent party with that firearm are vastly,
enormously greater than the chances of me even encountering a terrorist at
the airport. Even in the extraordinarily unlikely event that I did wind up
at the same airport at the same time as our hypothetical terrorists, how
would I know they were doing anything out of the ordinary? Should I draw
down on anyone who looks like a foreigner? On anyone who is loading
something into a plane? Should I open fire on any cropduster that I see
taxing to to active, especially if the pilot looks like "one of dem
Ay-rabbs"?

The reality is that the terrorist at the GA airport will look more or less
normal. The 19 butt nuggets who killed so many of our countrymen didn't
look in anyway abnormal on the morning of September 11th. Our hypothetical
GA terrorist will do the same thing, and look like just another guy getting
into an airplane.

I make my living as a statistician, so I have a certain fondness for
probabilities. For myself, given the way I live and the way I fly, the
probability of deriving any benefit from a loaded firearm at the airport is
just marginally greater than absolute zero. The chance of that loaded
firearm causing problems for me, due to uncomfortable passengers, nervous
police officers, concerned line personnel, and nosy bystanders is all but
certain over any long period of time. That's not even getting into the very
real risk that said firearm would be used against me, or that an accident
with it would hurt myself or somebody else. Simply stated, the costs
clearly outweigh the very unlikely expected benefit, at least for me.

There may be some people out there who are in a different situation, and who
are much more likely (for some reasons that I can't conceive of) to encouter
a GA terrorist at the airport. For these people, whoever they are, the
benefits may outweigh the costs. But not for me.

... then you're the only handgun owner I've ever heard of who seems to
refuse to be vigilant. Please reconsider.

I am vigilant. I am concerned about my safety, my passengers' safety, and
the safety of my nation. But I simply don't feel that, in my own situation,
being armed while out the airport increases anyone's safety. To the
contrary, I feel that it would make everyone involved marginally (but
significantly) less safe.