This was the worst fake job ever. There are so many pictures proving this. And the planes of 911 were live CGI. They were created with the AVID video system. It was far from perfect, but it did the job. But it left artifacts which are visible to the trained eye.
The wingtips of an airliner are made of hollow aluminum. They could not -repeat could not - slice through a concrete and steel building. It would be like butter cutting through a knife.