During Dee's confrontation with Renfield in the bathroom of the airport, in some shots Renfield is standing directly behind him, while in other shots he appears to be standing more to Dee's side.
When Renfield first attacks Buck Kendall, blood runs down his face and over his left eye. In shots immediately following, there is no blood spatter on his face, only slash marks.
He kicks a gravestone sideways, but in the next shot it's leaning forward.
Richard is leaving a small rural airport when he swerves to avoid hitting an oncoming pickup truck. As he does this you hear the squealing tires but he is driving on a dirt road.
The beacon lights at the airports depicted are a white or blueish light sweeping left to right. Real civil land airport beacons are alternating green and white lights that rotate.
There are many shots of Richard Dees flying his Beechcraft Bonanza plane without a headset on. No-one flies this type of light plane without a radio headset on at all times.
Richard is leaving a small rural airport when he swerves to avoid hitting an oncoming pickup truck As he does this you hear the truck's air horn with Doppler effect as it passes by. This air horn is the same sound effect heard in countless movies and TV shows and is of a semi-truck. There is no visible air horn on the pickup truck in this scene and was never stock equipment on this vehicle.
When Richard encounters the black dog, the animal is clearly discomforted by the wire apparatus used to retract its lips and reveal its fangs, trying to ease it away with its left paw.
Obvious double when Richard's plane is approaching the camera.
When Richard is in the graveyard he cuts his finger with a Swiss Army knife, however blood trickles onto his finger before it has made contact.
When Richard goes "to hell" there is a close-up of a vampire's face and the contact lenses used are extremely visible.
During Richard's first altercation with Morrison, the boom mic is clearly visible for a short while above the latter's head.
In the scene when Richard is scolding "Jimmy", when he's talking about her working on low-grade assignments.
When Richard is landing his plane the first time (0:21:40 mark) the pilot has a mustache, but when the camera goes to a close-up shot Richard does not have a mustache.