Extreme Makeover - When Cosmo made Timmy's wish, a poof cloud reads "Extreme Makeover Poof!", Then, when Wanda unwished Timmy's wish the poof cloud reads "Extreme Un-Makeover Poof!" which makes a reference to the show.
Air Force - The name of the destroying hair force "Hair Force" is a pun on the "Air Force".
When the fishbowl breaks, the castle suddenly disappears.
When Timmy's hair falls on Dimmsdale, Timmy had some hair on his head, but in the scene where he pops out the hair, he is bald.
At the scene where Timmy, Cosmo, Wanda, and Poof are in the bathroom, Poof looks smaller in size than he normally does.
In the scene at Baby Barbers, the barber reads Chapter 1 of a fairy baby haircut book. However, the page he is on is halfway through the book, despite it would be around page 7 (2-7 being the title again, etc.)
When Mr. Turner appears from the garage, the garage appears standalone, with the sky and no house visible to the right, as the sky on the left has the same color as the right-hand side of the garage.
Timmy: This is the worst hair cut ever! [mirror crack]
Timmy: I wish my hair can be cut!
A.J.: Hey, I have hair! I'm hot!
Timmy: A professional barber? This is awesome!
Chet Ubetcha: This is Chet Ubetcha saying Dimmsdale is the most dangerous city in the world, because it's being destroyed by a hairicane! Wait, I just got word that the Hair Force has been called in to tame this violent hairicane. We're saved... (the planes get destroyed by lightning and the Hair Force soldiers fall to the ground safely) And by saved, I mean "doomed"!
Timmy: Okay, that was good I got another A. But bad because my hair is getting out of control. But good because Mr. Crocker is in pain. Wait, why was it bad again? Oh yeah. BECAUSE MY HAIR IS OUT OF CONTROL!!!
Timmy: (to his hair after it threw Trixie away) Hey, what'd you do that for? Wait, are you jealous of Trixie? Look, when I said I loved you, I meant it in a brotherly boy and his hair sort of way. (Timmy's hair captures Chester and A.J.) You're jealous of my friends too?! First, you get me an F and then you get rid of my friends? Maybe I should get rid of you! What do you think of that?
Timmy: (screams as his hair turns into a hairicane) I think it made you mad, which is why it's time to clip this wish! Cosmo! When I said I wanted hair with personality, I didn't mean obsessive!
Cosmo: Well, maybe you need to be clearer with your wishes!
Timmy: Okay, I'll be clear now! I wish my hair was... (gagged by his hair)
Cosmo: Nope, still not clear! And you really shouldn't talk with hair in your mouth!