Quoting Russell Coker (russell@coker.com.au):
Yes, I was thinking about that one, specifically, when I wrote the upthread posting. The Piper PA-28 Cherokee the attacker used (in that case) is fairly typically of general-aviation aircraft, massing 544 kg empty (975 kg fully loaded) with a maximum speed of 230 km/hr. A tonne traveling at 230 km/hr is certainly going to kill multiple people at the point of impact, but OTOH isn't likely to produce mass casualties _in general_. On the third (gripping[1]) hand, as you note:
Of course if he had flown his plane into a crowd (superbowl or something) there would have been many more deaths and injuries from the crash and more from the stampede.
Quite possibly. [1] In-joke for readers of Niven & Pournelle's _The Mote in God's Eye_ and its sequels.