Those 19 did not pay their own room and board, they didn't pay their own tuition to flight schools and colleges. The Muslim terrorists living in the US are a well-financed group and much of their money is coming from US mosques. The average Muslim may or may not know they contribute to terrorism through their "charities". Back in 1998, it was estimated there were 1500 to 2000 known terrorists living in the US. "Jihad in America" is a good video to watch to learn more what the FBI knew all along.
Hey, the FBI used to assume everyone in the militias was a potential terrorist. Think of how many resources they used up chasing the Randy Weavers and the Eric Rudolphs. Those guys paint with a pretty broad brush, Fitz.
I say, forget this wacky and counter-productive plan to deport all aliens. Even if it were possible it wouldn't make America any safer. If you want to try a radical initiative, why not set up a Christian country somewhere in the Middle East? Somewhere the Ten Commandments and the Bill of Rights are respected, and people can get ahead by the sweat of their brow. Show the Arabs what can be done under US guidance and values, the same way Japan showed the Asians.