According to The Associated Press, nearly all air travelers entering the U.S. will be required to show passports beginning Jan. 23, including returning Americans and people from Canada and other nations in the Western Hemisphere. The date was recently disclosed by Homeland Security Secretary Michael Chertoff in an interview with The Associated Press. Until now, the department had not set a specific date for instituting the passport requirement for air travelers, though the start had been expected to be around the beginning of the year. Setting the date on Jan. 23 pushes the start past the holiday season.