A cockpit tape from the hijacked plane which crashed in Pennsylvania on 11 September 2001 was played to a US jury.
A video of the plane's flight path, altitude and speed based on information from the flight data recorder was also shown.
Flight 93 crashed into a field in Somerset County, Pennsylvania, killing all 40 passengers and the four hijackers.
The jurors are sitting in the sentencing trial of Zacarias Moussaoui, the only man to be charged in connection with the 9/11 attacks.
The Flight 93 audio recording is the only tape investigators were able to hear from any of the four hijacked airplanes.
Victims' families who have also heard the tape objected to it being released to the public.