OK, for all of those ranting about "threats" from GA aircraft, we'll believe that you're really serious about controlling "threats" when you call for:
- Banning all vans within cities. A small panel van was used in the first World Trade Center attack. The bomb, which weighed 1,500 pounds, killed six and injured 1,042.
- Banning all box trucks from cities. Timothy McVeigh's rented Ryder truck carried a 5,000-pound bomb that killed 168 in Oklahoma City.
- Banning all semi-trailer trucks. They can carry bombs weighing more than 50,000 pounds.
- Banning newspapers on subways. That's how the terrorists hid packages of sarin nerve gas in the Tokyo subway system. They killed 12.
- Banning backpacks on all buses and subways. That's how the terrorists got the bombs into the London subway system. They killed 52.
- Banning all cell phones on trains. That's how they detonated the bombs in backpacks placed on commuter trains in Madrid. They killed 191.
- Banning all small pleasure boats on public waterways. That's how terrorists attacked the USS Cole, killing 17.
- Banning all heavy or bulky clothing in all public places. That's how suicide bombers hide their murderous charges. Thousands killed.
Number of people killed by a terrorist attack using a GA aircraft? Zero.
Number of people injured by a terrorist attack using a GA aircraft? Zero.
Property damage from a terrorist attack using a GA aircraft? None.
I agree. The empirical data just isn't there to support a ban.
Humans have evolved a risk assessment mechanism in which we weigh more recent events, and more unusual events, more than less recent, less splashy ones. It's not a terrible proxy when you're in a fairly stable natural environment, where your main threats are things that are likely to recur over long periods and have limited impact. For instance, if you're in an area with sabre-tooth tigers, and you see someone eaten by one, the powerful incentive it gives you not to play with sabre-tooth tigers is a good thing and likely to be useful in the future. And one sabre-tooth tiger can't wipe an entire city off the map before someone reacts to it and deals with it.
Nowadays, though, we have technology, which amplifies everything including risks. And many of those risks aren't apparent without statistical analysis. If we take action using the old instincts, we do so at our peril. Animals use those instincts because that's all they've got. Humans have the capability to perform a more accurate assessment. We also have the need, because resources we use to protect ourselves against one potential threat are resources we're not using for a different one. And some of these risks really can wipe out a city or worse, so we need to deal with them before they happen. In light of those issues, banning light airplanes is a just plain silly waste of resources.