4 points
The B-25 bomber and Boeing 767 airliner are two very differet aircraft.
The WTC towers and the Empire State Building were also very different buildings.
So there events are not really comparable.
1 point
The point was that New York City saw a large plane hit one of its largest buildings. The failure mode was known. It just happened to be that no one cared to design for that failure mode later.
3 points
The last plane crash into a building in NY before 2001 was back in 1946, when a transport aircraft from the US Army Air Forces flew into 40 Wall Street.
That was 55 years before 9/11, and 20 years before construction of the twin towers was started, it was believed to be a solved problem, which in context wasn’t that unreasonable.
