From the 911 Staff Report, pg. 8:
"OVERVIEW OF THE HIJACKERS' ENTRIES
"The hijackers successfully entered the United States 33 of 34 times, with the first arriving on January 15, 2000, at Los Angeles International Airport.
All others entered through 8 airports on the East Coast, including 11 entries through New York area airports and 12 through Florida airports.
The four pilots passed through immigration and customs inspections a total of 17 times from May 29, 2000, to August 5, 2001. Ziad Jarrah was the most frequent border crosser, entering the United States seven times. Mohamed Atta and Marwan al Shehhi came in three times each, entering for the last time on May 2 and July 19, 2001, respectively.
"Hani Hanjour was the only hijacker to enter on an academic visa, arriving on December 8, 2000. He had already attended both English and flight training schools in the United States during three stays in the 1990s. Hanjour was also the only pilot who already had a commercial pilots license prior to entry, having acquired it in 1999 in Arizona.1
" Though Khalid al Mihdhar and Nawaf al Hazmi came to the United States as early as January 2000, the remaining muscle entered between April 23, 2001, and June 29, 2001. They arrived in six pairs and one trio. Four pairs were processed by the same immigration inspector. Only three of the muscle were referred to a secondary inspection for further scrutiny. Of these, only one, Mohamed al Kahtani, was refused entry to the United States.
" Entering the United States as tourists was important to the hijackers, since immigration regulations automatically guaranteed tourists six months of stay. Thus the 14 muscle hijackers who entered the United States in the spring and early summer of 2001 were able to remain in the country legally through September 11. The six-month tourist stays also assured the hijackers of sufficient time to make such preparations for their operation as obtaining the identifications some of them used to board the planes on September 11.
" Fourteen of 15 operatives and all of the pilots acquired one or multiple forms of U.S. state-issued identification. Only Satam al Suqami did not, possibly because he was the only hijacker who knew he was out of immigration status: his length of stay end date of May 20, 2000, was clearly inserted in his passport."
You need to find another excuse to build your wall to keep out Mexican laborers. Arguments that work with the anti-Hispanic crowd that has recently been attracted to FR aren't going to fool the people making the decisions.
That's funny; I've never advocated building a wall.