United Flight 93 slammed into the ground after passengers on board acted heroically and stopped the hijackers from crashing into their intended target in Washington DC. The film will trace the plane's last 90 minutes from take-off until it crashed in Pennsylvania.
According to Variety, "Flight 93" will be shot using hand-held cameras and will be, in large part, improvised.
Greengrass most recently directed "The Bourne Supremacy" for Universal Pictures. He has "Watchmen" and "They Marched Into Sunlight" in development.