Just an FYI, on 9/11 Donald Trump was interviewed by channel 9 out of New York. He said that he had recently been in one of the towers due to a bomb going off in the basement, and one of his structural engineers had taken him to see the damage. He said half the columns were blown out, But, the tower was built so well that it was standing strong. He also said the basement is the most vulnerable places in tall towers. He said this was because of the way the towers were built with so much steel on the outside of the building. He mentioned the windows were very narrow because of all the steel used. When asked about the planes being able to cause the collapse, he said he thought that there had to have been explosives either on the plane, or in the building.
Then, they had the investigation, there were several people who had questions about it. I saw somone ask a NIST person if they checked for explosives and he said no.
You can find this interview on youtube.