My argument basically hinges on heuristics.
First, Al-Qaeda being slang for "the toilet," specifically a Western toilet, points to them being
1. Fake, since no serious militant organization would call themselves "The Toilet"
2. Of foreign/Western, not necessarily Israeli or American, origin
Second, Israel has been attacking the US using "Islamic Fundamentalism" as a proxy since its inception. In the Lavon Affair, they bombed US, British, and Egyptian buildings and tried to frame the Muslim Brotherhood for these actions to get the British to station troops in the Suez Canal area. This is not conjecture. This is a matter of historical record.
Third, pretty much all the people involved with running the WTC towers and privatizing assets that would have been useful in preventing the attacks were Israelis/Zionists. Plus, they managed to avoid getting killed in the buildings they worked in. The man who owned the buildings ate breakfast at the Windows on the World cafe every morning from when he bought the 99 year lease on the towers to when the attacks came, but mysteriously forgot to do this the morning of 9/11. Same with his family members, who also worked in the towers but "couldn't come in" on that exact day.