Factual error: The extractor fan shouldn't have sucked the hair into the kitchen, as extractor fans blow air from inside to outside.
Continuity mistake: When Stifler is in the linen closet it is completely dark. Finch and friend open the door and the closet is lit. After that they close the door, but the inside of the door remains lit. When the shot changes to the other side, the closet is completely dark again, without a source to light the inside of the door.
Continuity mistake: Throughout the film, Michelle's hair changes from being long to shorter to longer again. It's easy to spot when she is wearing her hair down.
Continuity mistake: The lettering on the cake at the beginning changes after Stiffler messes it up. It's in a row then diagonal.
Continuity mistake: During the bachelor party, the cop stripper rips open her top and shoves Michelle's mother's face into her chest. In the next shot the stripper's top is buttoned.
Character mistake: When Cadence meets the group at the airport and Finch comments "you're reading Descartes", she responds by utterly butchering the line "cogito, ergo sum." Odd that a student of Descartes would be unfamiliar with how to pronounce his most famous statement-somewhat analogous to a student of Einstein not knowing e=mc^2.
Continuity mistake: When Jim's dad goes to see Michelle (when she's trying to write her vows), her hair and makeup are done for the wedding, and her hair is in a French twist. Later, when Michelle and Jim are having their first dance, her hair is in a curly bun sort of style.
Answer: As I remember, there was a scene where someone says, "Michelle's parents are flying in for the wedding."