The commission's report on the tower collapses was that the middle cores of the buildings were pretty much hollow, only being used for elevators and utility lines. But there most certainly were steel beams, a lot of them, in the cores, and they have pictures of them under construction that prove it. And then there's the pulverized concrete. Not chunks, not shards, but powder. How the heck does that happen??

And notice how the jets kind of melted into the buildings. The wings didn't bend back, nothing sheered off at impact. Kinda like a hologram.