April 23-June 29, 2001: The 13 hijackers commonly known as the "muscle" first arrive in the US. The muscle provides the brute force meant to control the hijacked passengers and protect the pilots. [Washington Post, 9/30/01] They all pass through Dubai, United Arab Emirates, and their travel was probably coordinated from abroad by Khalid Almihdhar, according to FBI Director Mueller. [Congressional Intelligence Committee, 9/26/02] But some information contradicts their official arrival dates:
April 23: Waleed Alshehri and Satam Al Suqami arrive in Orlando, Florida. Suqami in fact arrived well before February 2001 (see February 2001). Alshehri was leasing a house near Washington in 1999 and 2000 (see 1999 (H)).
May 2: Majed Moqed and Ahmed Alghamdi arrive in Washington. Both arrived by mid-March 2001 (see Mid-March 2001).
May 28: Mohand Alshehri, Hamza Alghamdi, and Ahmed Alnami arrive in Miami, Florida. Both Mohand Alshehri and Hamza Alghamdi arrived by January 2001 (see January 2001 (B)). Hamza Alghamdi was living with Waleed Alshehri near Washington until July 2000 (see 1999 (H)).
June 8: Ahmed Alhaznawi and Wail Alshehri arrive in Miami, Florida.
June 27: Fayez Banihammad and Saeed Alghamdi arrive in Orlando, Florida.
June 29: Salem Alhazmi and Abdulaziz Alomari arrive in New York. Alhazmi in fact arrived well before February 2001 (see February 2001).
After entering the US (perhaps reentering for some), the hijackers arriving at Miami and Orlando airports settle in the Fort Lauderdale, Florida area along with Atta, Marwan Alshehhi, and Ziad Jarrah. The hijackers arriving in New York and Virginia, settle in the Paterson, New Jersey area along with Nawaf Alhazmi and Hani Hanjour. [Congressional Intelligence Committee, 9/26/02] Note that the FBI's early conclusion that 11 of these muscle men "did not know they were on a suicide mission," [Observer, 10/14/01] is contradicted by video confessions made by all of them in Afghanistan (see March 2001) and CIA Director Tenet later says they "probably were told little more than that they were headed for a suicide mission inside the United States." [CIA Director Tenet Testimony, 6/18/02] They didn't know the exact details of the 9/11 plot until shortly before the attack. [CBS, 10/9/02]

August 24, 2001 (B): Hijacker Khalid Almihdhar buys his 9/11 plane ticket on-line using a credit card; Nawaf Alhazmi does the same the next day. [Congressional Intelligence Committee, 9/26/02] Both men had been put on a terrorist watch list on August 23. Procedures are in place for law enforcement agencies to share watch list information with airlines and airports and such sharing is common, but the FAA and the airlines are not notified, so the purchases raise no red flags. [Los Angeles Times, 9/20/01] An official later states that had the FAA been properly warned, "they should have been picked up in the reservation process." [Washington Post, 10/2/02]

August 24-29, 2001: The hijackers book their flights for 9/11, using their real names. Most pay using credit cards on the internet. [Miami Herald, 9/22/01] So 9/11 must have been the confirmed date of the attack by August 24. Why would they pay using credit cards in their real names? Or were they names we know them as actually stolen identities?