Annette opens a kitchen cabinet and replaces two jars of peanut butter on a shelf filled with nothing but Skippy peanut butter (10 jars). Annette Funicello was the star of a series of television commercials for Skippy peanut butter at the time. (The other shelves are similarly strangely stocked: the top shelf is nothing but Heinz ketchup (16 bottles), while the next is nothing but Campbell's soup (29 cans)).
The initial external shot of the airborne Boeing 747 is a full-length version of the plane. Upon landing, it is clearly the much-shorter "SP" version of a TWA 747.
During the Big Beach Bonfire Party, Annette starts out wearing an orange sweater over a sparkly white top and pants. Minutes later, she's wearing a bright pink wetsuit with a polka-dot skirt while she surfs with Troy. She goes off to find Connie in the very next scene and she's back to wearing the original outfit.