When Dean and Sam are talking with Jerry Panowski about a possible poltergeist, a co-worker walks by and says: "Poltergeist (1982)? I love that movie!" This comment was added in post and was not stated during filming.
Sam tells Dean to say God's name in Latin, "Christo", just as Dean is about to find out if Amanda has the demon in her. "Christo" is actually Greek, not Latin, for "Anointed One". If they wanted to be right they should have said "Christus".
Sam and Dean pose as Homeland Security agents: Jerry Wanek and Robert Singer. Robert Singer is one of the executive producers of the show and Jerry Wanek is the production designer. This was of course long before the character of Robert "Bobby" Singer was introduced.
Sam mentions Flight 401 a flight that crashed in the Florida Everglades. The airline really did salvage parts and placed them in other aircraft. While the airline denies any ghost stories, it has been alleged that the dead crew have appeared on these aircraft. The airline did remove all salvaged parts from the 'haunted' aircraft.
There are several aspects of the demon mythology that differ in this episode from the way demons are portrayed in later seasons. The demon smoke resembles a swarm of insects, unlike the more fluid cloud-like appearance in later seasons. In this episode only the iris of the eye is black, later the whole eye will be filled in. The holy water is shown to cause tissue damage to the host, when it is used on the demon; whereas in later seasons, the holy water rises off the host body like smoke and only harms the demon. While performing the exorcism the demon speaks in a strange deep voice; in later seasons demons speak using their host's regular voice. Demons also don't need to be summoned in future episodes as part of theexorcism ritual, in order to banish them back to hell. This is the only instance of a demon using EVP (electronic voice phenomenon); in the rest of the series EVP is a rare ability unique to ghosts.
First occasion where the boys wear suits as a disguise, to gain access to a crime scene. In this case, they wear all black suits and pretend to be Homeland Security with fake ID's, but the suits later become known as "the Fed Threads."
When told about the plane crashing near Nazareth, Dean makes a comment about the irony of it. The pilot who crashed the plane was trying to get over his fear of flying after surviving a plane crash. His facing his fear by flying again could be described as "hair of the dog that bit him." Hair of the dog is a well known song by the rock group Nazareth.