What Kind of Planes Hit the WTC and Pentagon?

Some intriguing findings here and here, suggesting other types of planes hit the WTC and Pentagonm than a 767 and 757 respectively. I have no idea how accurate the WTC engine identification is, but at least the part is intact enough to make some sort of ID. I have tended to doubt that flights 11 and 175 hit the WTC towers because there has been such secrecy about the black boxes, so if the engine is from a 737, that would make sense. Previous analyses had also suggested that the plane length was wrong for flight 175,so all this evidence tends to fit togehter to suggest that some other planes hit the WTCs-- particularly the South tower.

As far as for the Pentagon engine, I tend to doubt that the part shown in front of the Pentagon is really an aircraft engine. However there is some similarity and it is hard to completely rule out that it is not an engine.