Family Guy (1999)

Baby Not On Board - S7-E4

Plot hole: Stewie gets out of the car seat and goes back to bed, leaving the blanket at the bottom of the seat. When they get to New York, Lois goes to get him out and realises he's gone. But when they started the trip the blanket was covering the entire seat to make it look like Stewie was still in it. So who ever "covered" him up knew he wasn't in the seat before they set off. (00:13:45)

Lois: Hello?
Peter: I can't take the trash out today, I'm working late at the office.
Lois: The caller ID says you're calling from the kitchen. In fact I can see you.
Peter: [Edging sideways.] OK, can you see me now?
Lois: No.
Peter: Now I am at the office.

Trivia: The voices of Brian, Stewie and Peter (as well as other minor characters) are all voiced by the creator, Seth Macfarlane.