The flashback of a young Gus (Eastwood) are taken from this film for close-ups of his face.
Poster is shown in a video store.
A poster for the film can be seen in Williams' room.
The opening cloud shots were originally used for the Clint Eastwood movie Firefox (1982).
the Night Raven jet looks like the MiG-31 FIREFOX and also uses foreign-language commands instead of physical buttons to use the weapons
Mentioned by Mike.
"Are We Alone?" segment