Continuity mistake: When the Griffins are driving to Washington we see a faraway shot of the car driving from left to right. Peter and Lois are in the front and Chris is leaning back on the back seat. In the next shot, Chris is leaning forward against the back of Peter and Lois's seats.
Continuity mistake: When Peter enters the cockpit and accidentally kills the pilots the cockpit looks small enough so that it could only fit Peter and the pilots in their seats. However, when he turns around to leave the cockpit looks big enough to fit an entire group of people.
Add timeTobin OReilly
Continuity mistake: In the episode "Petarded", when Peter is in court, when he says he is going to call "the ghost that never lies" to the stand, only Stewie is visible over Peter's shoulder. But when Peter says "But only I can see him", Meg is also visible over his shoulder.
Continuity mistake: In series 4 episode 13 Jungle Love: When the family are escaping the tribespeople, Chris is wearing the tribal clothing. When they jump in the plane there is a brief far-off shot of Chris wearing his usual cap and t-shirt. In a close up shot moments later, he is wearing the tribal gear again.
Continuity mistake: After Lois accuses Stewie of peeing on the carpet, he asks her to bend down and slaps her with a glove. The glove remains in his hand in that cut, is still there when there is a wide shot of Peter, Stewie, Lois and Brian (you can just see it next to his trousers in his hand), but when it cuts back to Stewie and he starts on about "the outrages" etc, it is gone (the cut is instant, no time for him to put it back in his pocket). A common error, this one just struck me as strange, because the sandwich Stewie threw at Lois is there the entire scene.
Continuity mistake: In the scene where Lois goes down to the room where Peter is dancing, Peter is wearing blue pants. After he walks over to the door and greets her, he still has blue pants. The next shot of Lois and Peter dancing has him wearing his normal green pants, but after that it goes back to blue pants for the rest of the scene.
Continuity mistake: When Stewie is in the sterile glass cage, Lois is changing his diaper with rubber gloves built into one of the panels (like Homer Simpson's in the opening credits). In previous and subsequent shots, however, the panel is solid glass, with no gloves. (Series 4: The Father, the Son, and the Holy Fonz).