After taking over the plane, one of the hijackers places a photograph of their target, the U.S. Capitol Building, on the plane's yoke. Near the end of the film, when the passengers fight back and struggle with the hijackers for control of the plane, the picture is knocked off the yoke in the process, symbolizing that the hijackers will not hit their target.
The title itself also counts as a reference where passengers united against the foe to save countless more lives.
