Velma and Amber are at the stage side watching The Lafayettes, and at the same time, Velma is on the other side near the entrance making accusations against Traci to her mother; then she is back again with her daughter watching the Lafayettes.
During "Shake A Tail Feather," the non-council members in the background are dancing along in close-up shots, but just watching in the long shots.
When Tracy is modeling on the Corney Collins show, she eats a snowball that already has a bite taken out, then reverts to the original state before she picks it up.
When Seaweed visits Penny after the riot at Tilted Acres, he only cuts one bar with the bolt cutters but breaks out two bars. Also, when he dropped the bars behind him, the sound is of them hitting immediately behind him, not on the ground below, as he was breaking in on the second floor.
When the two kids in the red car pull to the curb, two boys in blue pants walk by twice.
In the closing credits, the 1988 production year is shown in Roman Numerals as "MCMDXXXVIII." It should be "MCMLXXXVIII."
The announcer for the 6:00 news gives the date as "Friday, June 5, 1962." In 1962, June 5 was a Tuesday.
The taxi cab that Penny's mother gets out of when she arrives at Maybelle's record store has a rear window defogger/defroster system not available on automobiles in 1962.
When its the Lady's choice thee song "You'll loose a good thing" by Barbara Lynn plays. It was released in 1963 however Hairspray takes place in 1962.
After Tracy Turnblad asks the Beatnik Chick how the latter straightens her own hair, she replies "With an iron, man." Addressing Tracy as "man" instead of a female term is not an error; the joke is that the beatniks would punctuate a sentence with "man" regardless of gender.
The Beatnik Chick's tattoo on her right arm clearly has tape on it, indicating her tattoo is not a part of her skin.
Seaweed, introducing himself as Maybelle's son to Tracy, mispronounces his own mother's name as "Mabel".
When Tracy Turnblad and her friends are in Motormouth Maybelle's record shop, The Supremes album "Supremes A Go-Go," from 1966, is behind them.
During tryouts for the Corny Collins Show, Nadine is asked if she can "relate to Lesley Gore's music." Gore recorded her first single, "It's My Party," in March 1963.
In his advertising spot on the Corny Collins show, Mr. Pinky states that his 'Hefty Hideaway' "clothes for the ample woman" are "available in size 12 to 26," which, in 1988, would have been considered 'plus size.' However, in 1962 sizing, a size 12 was not a 'plus size.' In fact, the approximate measurements, in 1962, for a size 12 dress would have been 32-25-34.
While they are watching "The Corny Collins Show" on TV, Wilbur Turnblad reads a "Life" magazine published March 19, 1965.
When Corny introduces himself at the auto show, the audio is not in sync with his lips.
During the picketing at Tilted Acres, a woman lights and throws a cherry bomb-type firecracker that makes the sound of a string of firecrackers exploding.
When Toussaint McCall is singing, he's clearly lip-syncing the record that's being played as his words don't quite match the song being heard.
As Penny's mom pays off the drunk, a camera shadow falls across her back.
The Maryland Governor's Mansion is in Annapolis, not Baltimore.
When The Lafayettes sing "Life's Too Short" on the Corny Collins show, they are presented as a three-man group. In reality, the group had seven members.