This is my new theory as to why the 2nd plane that is seen entirely penetrating through the South WTC Tower in the videos without crumpling, exploding, or any of the wings and tail section pieces being sheered off, and penetrates with no resistance as if it were passing through a cloud:
It was a Solid Stainless Steel plane!
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D.Duck has a competing theory, the Concrete Plane theory:
How about CPT (concrete plane theory).
The plane was a concrete plane, you can clearly see it with your own eyes that it turns to dust when it hits the south wall.
D.Duck
