Are covered here:
Moussaoui also says that he was to be the 20th hijacker, which does not appear to be true. He was arrested in Minnesota on August 16, 2001, at which point all the hijacking teams had all gotten together. According to KSM, Moussaoui was intended as a pilot in a second wave of the attacks.Zacarias Moussaoui, 46, says an unnamed Saudi Prince paid for flying lessons for him and the 19 terrorists who hijacked planes in the September 11 attacks in the run-up to the atrocities.The incredible claims were made in documents filed to a federal court in Oklahoma, in which Moussaoui says a prince 'was assisting me in my Islamic terrorist activities... and was doing so knowingly for Osama bin Laden'.He also said that bin Laden assistance from Saudi leaders in planning the attacks, and that he was involved in a plot to shoot down Air Force One with President Bill Clinton on board
The claim that a Saudi prince financed him is more interesting, as it apparently comes in depositions as some of the 9-11 families are suing Saudi Arabia. There are some obvious red flags, though. First, as the article notes, Moussaoui does not have terrific credibility; his story has changed many times. Second, his funds were sent by 9-11 paymaster Ramzi Bin al-Shibh; how would he have knowledge of the ultimate source of the funds?
There may have been at some point a plot to shoot down Air Force One, but Moussaoui wasn't even in America during Bill Clinton's term. He arrived in February 2001, after George W. Bush had been inaugurated.