There's a lot of mechanics (both material and structural) that go into analyzing events like this, but yes it appears that very evil people planned and carried out bringing the towers and building 7 down, and the pentagon was a directed missile strike and coverup from what I've seen as well. For starters as far as the airplane vs. building, you have to consider that the strength of a material in the direction of force is a cubed factor (a*b^3). For example a 10mm thick plate 100mm wide will be a LOT stronger if the wide end is vertical as a structural member, vs. if it's laying flat. This is why you see "I" beams holding up building floors with the widest part vertically oriented. When you start getting into the material properties ("compressive force"), that is another aspect to be considered. Concrete has a compressive strength of 2500 to 10k PSI, whereas 2024 aluminum (typically used for aerospace applications) has a compressive strength of ~40 kPSI. but with the cube factor of flooring in the direction of the force, concrete maybe 2" thick above corrugated steel (think of the horizontal floors now having that cubed factor working for them) vs. the planes wall thickness of maybe an 1/8", and you'd have to at best assume the plane had to hit at a perfect right angle to even have a chance to take down the building. This assumes something happening right at the impact. But the aluminum would crumple, and lose that cubed strength factor pretty quick.

The real tell-tale was the building coming straight down. It would be about impossible that all the support beams would give out together in unison. It would be way more likely one corner or side would buckle first, and the building start toppling in another direction, which it obviously didn't.