Here's mine:
I am in favor of armed pilots. If there had been just one firearm on each of the hijacked planes, we would have prevented the deaths of 6,000+ Americans, 40 billion+ dollars of property damage, and one trillion+ dollars of world stock market losses.
.38 cal ammo costs $12 to $15 per box. There are fifty rounds in a box, for a per-round cost of $.24 to $.30 per round. There were 18 hijackers and, if one assumes each required two shots, all of the above could have been prevented with a maximum $10.80 investment.
Do the math.