8:00am - American Airlines Flight 11, Boeing 767 with 92 people aboard, takes off from Boston's Logan International Airport for Los Angeles.
8:14am - United Airlines Flight 175, Boeing 767 with 65 people aboard, takes off from Boston's Logan airport for Los Angeles.
8:21am - American Airlines Flight 77, Boeing 757 with 64 people aboard, takes off from Washington Dulles International Airport for Los Angeles.
8:40am - Federal Aviation Administration notifies North American Aerospace Defense Command's Northeast Air Defense Sector about suspected hijacking of American Flight 11.
8:41am - United Airlines Flight 93, Boeing 757 with 44 people aboard, takes off from Newark International Airport for San Francisco.
8:43am - FAA notifies NORAD's Northeast Air Defense Sector about suspected hijacking of United Flight 175.
8:46am - American Flight 11 crashes into north tower of World Trade Center.
9:03am - United Flight 175 crashes into south tower of World Trade Center
9:08am - FAA bans all takeoffs nationwide for flights going to or through airspace around New York City.
9:21am - All bridges and tunnels into Manhattan closed.
9:24am - FAA notifies NORAD's Northeast Air Defense Sector about suspected hijacking of American Flight 77.
9:26am - FAA bans takeoffs of all civilian aircraft.
9:31am - President Bush, in Florida, calls crashes an "apparent terrorist attack on our country."
9:40am (approx.) - American Flight 77 crashes into Pentagon.
9:45am - FAA orders all aircraft to land at nearest airport as soon as practical. More than 4,500 aircraft in air at the time.
9:48am - US Capitol and White House's West Wing evacuated.
9:59am - South tower of trade center collapses.
10:07am (approx.) - United Flight 93 crashes in Pennsylvania field.
10:28am - North tower of World Trade Center collapses.
11:00am - New York Mayor Rudolph Giuliani orders evacuation of lower Manhattan.
1:04pm - From Barksdale Air Force base in Louisiana, Bush announces U.S. military on high-alert worldwide.
2:51pm - Navy dispatches missile destroyers to New York, Washington.
3:07pm - Bush arrives at US Strategic Command at Offutt Air Force Base in Nebraska.
5:25pm - Empty 47-story Seven World Trade Center collapses.