6:00: Mohammed Atta travels Colgan Air from Portland International Jetport in Portland, Maine to Logan International Airport in Boston, Massachusetts, along with Abdulaziz al-Omari.[1]
6:45: Atta and al-Omari arrive at Logan International Airport.[1]
6:52: Marwan al-Shehhi calls Atta from another terminal at Logan to confirm that the plans for the attack are set.[1]
7:00 a.m.
7:35: Atta and al-Omari board American Airlines Flight 11.[2]
7:40: The rest of the Flight 11 hijackers board the airplane.
Where'd they "board Flight 11"? Hint: Logan, in Boston.
HTH.