I was originally going to write something very different about wing impacts, but after doing some further examination of the topic, I realized I needed to rethink things.
This diagram shows a simulation of a Boeing 767 (in AA colors) going into the WTC North tower about where AA11 is alleged to have hit and at a similar angle as how AA11 is alleged to have hit (the flight simulator program allows you to fly through many large buildings with any impedence):
(click to enlarge)
Here, the wings are just starting to go into the tower. I've marked several things in the image, but what is most striking is the relative size of the columns at this angle compared to the wings. Note-- the column cross-sections (the little yellow squares) may not be perfectly scaled, but the relative proportion of the columns to the wings is very close.
When I made this diagram, what struck me was the huge width (horizontal surface) of the wings in relation to the cross-section (horizontal cross-section) of the outer columns.Now,
as indicated by the fact that a bird can smash through the outer aluminum skin of the wing, I've no doubt that the leading surface of the wings would be crushed on impact with the heavy steel of the WTC columns.
However, there is so much wing material that impacts the columns because of the horizontal surface of the wings (roughly 20 feet wide near the fuselage, 10 feet wide in the middle, and about 5 feet wide at the tip), that it changes this equation, I think. In particular, the inner wings, the parts of the wings bearing the landing gear and engines, have a great deal of mass.
Thus, it is conceivable to me that the overall mass of the wings-- the large horizontal mass of aluminum piling up at high-speed at a concentrated section on an individual column-- could lead to column severing to the extent that was seen here:
Of course, it is NOT clear what would have happened to these wing sections once they got inside. If they were strong enough to get through the steel columns, it is not clear what would have destroyed them once inside. Yet we have not seen one picture of a wing section recovered from Ground Zero. (Of course, the black boxes officially were not even recovered from Ground Zero.)
Furthermore-- my tendency is STILL to think that the wingtips would have shorn off by the diagonal force exerted by the columns along the length of the wings (see arrows in top image). This force should have driven the wings backwards such that the very outer tips would never make contact with the columns and left an imprint. We know the outer 20 feet of the port wing could not have entered the tower intact, and thus some part of the wing HAD to shred upon impact.
Still unresolved for the official story is what happened to the wings where the columns were not severed and were just "impacted"-- for instance, the last 7 columns columns of the facade scar on the North tower as shown above. Did the outer wings shred and pass completely between the columns in the windows? Or did the wings shred and most of the material was deflected backwards? Either way, that is a lot of aluminum to shred and it is far from clear what happened to all this material.
Furthermore, the effect of the wings on individual columns is quite different than the phenomenon of the wings apparently penetrating concrete and metal floor slabs, as seen here in a video of the south tower attack:
Whereas individual columns present only 14 inches of horizontal material for the wing to penetrate, floor slabs obviously present a much larger horizontal obstacle. Thus, this image of the 2nd hit (for many reasons actually), still seems patently bogus to me.
There is also the issue of how the aluminum shredding and penetration of columns should have slowed the plane down as it went in. If the wings stayed attached to the fuselage (i.e. didn't break off) as the wings shredded against the outer columns, this would seemingly slow the plane significantly (which of course was not seen in the South tower videos).
Ultimately, all this does not prove that Boeing 767's hit the towers-- I still think there is a great deal of evidence against that-- but rather that the severed columns by themselves are not proof against the official story.
The wing scars MAY be evidence against Boeing 767 impacts, although the argument is more complicated.
My general impression is that "someone" was trying REAL HARD, by making the building gashes the exact wingspan of a Boeing 767, to make it look like Boeing 767s hit the towers.
Another factor is that the tower scars defy physics in general, since objects that can crash through another object and leave a cut-out shape of themselves shouldn't be destroyed at the same time they are making the cut-out shape.
Ultimately, I am still convinced that a Boeing 767 did NOT hit the South tower, and therefore it is not clear why they would lie about the South tower and not the North tower.