When the CIA are scanning Al-Mihdhar's travel documents, his ticket shows the airline to be Dubai Airways. No such airline existed at the time.
At the border crossing in Washington, a Chrysler sedan has an Ontario license plate beginning with three numbers. Ontario plates begin with four letters.
While on the stakeout, Soufan tells Chesney that he's going to "noon" prayer. When Soufan is shown praying in the Mosque, his wristwatch indicates it is 10 mins. after 9:00.
The border guards in Washington in 1999 have Department of Homeland Security patches on their uniforms, despite the agency not having been created yet (it would assume operations in 2003).