From the History Commons Groups blog:

A large number of entries have been added to the Complete 9/11 Timeline at History Commons. Many of these examine the response of American Airlines to the hijacking of Flight 11, the first plane to hit the World Trade Center on September 11, 2001. Entries focus, in particular, on phone calls made from Flight 11 by two of the plane's flight attendants: Betty Ong and Amy Sweeney.

A new timeline entry describes how Peggy Houck, a dispatcher at the American Airlines System Operations Control (SOC) center in Texas, received her first indication of a problem with Flight 11 when another American Airlines flight contacted her at 8:20 a.m. and said air traffic controllers had asked it to try to contact Flight 11.

Betty Ong's Phone Call from Flight 11

American Airlines employees who were dealing with phone calls made by two flight attendants on Flight 11--the first plane to be hijacked on September 11, 2001--were told by their superiors to keep quiet about what they had learned about the unfolding crisis. At a time when the airline should have been alerting as many people as possible to the serious incident that the flight attendants were describing, senior personnel were instead issuing instructions such as "Don't spread this around" and "I don't want this spread all over this office right now."

Furthermore, airline employees who were aware of the flight attendants' calls were remarkably slow to pass on what they knew to individuals and agencies that should have been alerted as a matter of urgency, such as the FBI, the FAA, and even American Airlines senior managers.