Am confused about the twin tower attack?

they didn't, they used knives and took advantage of the fact that up until that point, hijackings typically ended up with the plane being flown somewhere and negotiations held, and not being used as suicide weapons.

It's my understanding that box cutters and no guns were used.

I don't mean to offend anyone. It's just my belief.... If you watch the footage too...bombs were planted on different floors of the building. You can see as they blow up in series the different floors start collapsing.
A plane would only destroy the area of impact in a blow and the rest would lean before disrupting in a havoc. Not just collapse in on itself so neatly.
Therefore definitely there was inside job involves.

Plastic knifes I think