At the beginning of the film Vada'a English teacher asks his class to write a paper about someone that they don't know. When questioning the class one of Vada's classmates says that he wants to write about Farrah Fawcett, due to the fact that he likes to watch her run on television, an obvious reference to her role on Charlie's Angels (1976). However, the film takes place in 1974 two years before Charlie's Angels premiered in addition Fawcett, although working as an actress, was a mostly an unknown at the time.
During the scene in which Vada and Nick are speaking to the director on a Studio back lot, it is quite clear that the distinctive show building for "Back to the Future: The Ride" is visible on top of the hill in the background. The ride, which is located on Universal Studios' "upper lot," was not constructed until 1992.
When Vada's plane lands as the end of the movie the hill behind the airport with all the houses on it does not look like anything that would be found in Pennsylvania but looks quite similar to southern California.
When Vada's plane leaves for California you see her flying over a coast, with the land on the right side of the plane. There are no major bodies of water between Pennsylvania and Southern California. Lake Erie is the closest major body of water that the plane would fly near, however, since Lake Erie is north of Pennsylvanaia the coast would be to the left of the plane as it flew west.
in an earlier scene, Vada and her family were watching "the Partridge Family". when Vada and her father go bowling she mentions missing Archie Bunker, however, in 1974 (when the movie is set) The Partridge Family and All in the Family were shown at the same time on the same night, so she'd already missed Archie Bunker while she was watching The Partridge Family.
Near the beginning of the movie, when Vada and Harry go bowling and Vada rolls her strike, just as the ball touches one of the pins, you can see that all of the pins were yanked backwards as if strings were attached to each of the pins.
When Vada and Judy are looking at perfume, Vada chooses "Passion Fruit", turns the bottle over, and reads the description of the perfume. But in the next shot it is apparent that there is no label on the back of the perfume bottle.