Yemenis Walid Muhammad Salih Bin Attash aka "Khallad" and Bin al-Shibh tried to obtain U.S. visas but were denied. Sheikh Mohammed noted that Bin al-Shibh was living in Germany when he tried to obtain a U.S. Visa but was still denied.
9. Sheikh Mohammed dispatched Bin Attash [(a.k.a. "Khallad")] to southeast Asia in December 1999 to observe security measures on U.S. carrier's east Asian travel routes in preparation for this operation. When Bin Attash [(a.k.a. "Khallad")] returned, he reported that airline security officials had questioned and searched him thoroughly, but since Sheikh Mohammed was not planning to have operatives smuggle weapons on board the flight, he did not believe this scrutiny would pose a problem for the operation.
10. Sheikh Mohammed stated that in January 2000, the four operatives involved in the planes operation flew to Kuala Lumpur, Malaysia. Khallad, al-Hazmi, and Abu Bara flew from Karachi, whereas al-Mihdhar flew from Yemen and joined them there. Khallad's and Abu Bara's mission in East Asia was to ride a U.S.-flagged commercial airliner to gain familiarity with riding on U.S. planes...Sheikh Mohammed stressed at this point in the planes operation, all four operatives only knew that they had volunteered for a martyrdom operation involving planes; al-Midhdar and al-Hazmi knew
