Among many differences from the source material, in the book, the zombie-like infected continue to have their brains re-written every night and evolve further psychic abilities, including telekinesis, which allows them to fly. This is explained as the infection having unlocked the human brain's latent supernatural potential. This idea is only vaguely alluded to in the film when the survivors of the boys school explain that the human brain is like a computer and that this could be the next stage in human evolution.
When Clay Riddell (John Cusack) sits on his son's bed, he faces a painting of a ship on stormy waters hanging on the wall. It is the same infamous painting which hung on the wall of Mike Enslin's (also played by Cusack) hotel room in Stephen King's Chambre 1408 (2007).
Stephen King announced in 2009 that he had written a screenplay for the movie, and had created a new ending, based on reader complaints about the book's ending.
In the airport, the flight to Manchester, New Hampshire is changed to gate A6. A6 is the lethal virus strain from the Stephen King novel "The Stand" (1978).
In the airport, the intercom announces, "Flight 1408 to Los Angeles". This is a reference to the Stephen King short story and movie Chambre 1408 (2007).
Lloyd Kaufman: the co-Founder of Troma Entertainment and director of films like Toxic Avenger (1984) and Tromeo and Juliet (1996), in the opening airport scene as the bystander in a blue Hawaiian shirt.