After 9/11, policies were put in place to address flaws in airport security. How many planes have intentionally been flown in to buildings since then?

After the Oklahoma City bombing, policies were put in place to regulate the sale of ammonium nitrate. How many buildings have been blown up by truck bombs since then?

I've seen the rhetoric from the pro-gun side after each one of these mass shootings claiming that there isn't anything to be done to prevent these acts. Are you sure about that? Are you sure that regulations that limit access to weapons of war won't mitigate the amount of damage that can be done when someone goes off the rails? This guy acquired the bump stock to improve his rate of fire. Perhaps, without this retrofit, the body count is a little lower.