While flying in the airplane, Joe asks Quagmire if he'd like a bite of his Mounds candy bar. However, the wrapper is blue and white. Almond Joy comes in that color wrapper. Mounds is red and white.
In the "Back To the Future" cutaway, Lorraine McFly tells George McFly that she hasn't seen Marty "from high school" since the prom. George, Lorraine, and Marty actually attended the Enchantment Under the Sea dance in November of 1955, not the prom, which is usually held in May.