"And, I agree, if it is now known that Atta had entered the Unied States in 2000 on false documents"
Atta flew to Newark from Prague in 2000. He actually made two trips to Prague before flying to the U.S. The first was by plane, in which he stayed at the Prague airport for a few hours before flying back to Germany. After obtaining a German visa, he then took an overnight bus back to Prague, entering the Czech Republic around 6:00 A.M. He stayed in Prague, whereabouts unknown, for most of that day, before flying on to Newark. These trips are documented. The obvious question is, why did Atta go to Prague? Plenty of plane flights from Germany to Newark.
I thought those trips to Prague were in early 2001...