Continuity mistake: When Linus and Snoopy enter the theatre where the spelling bee is taking place, you can see they are entering from the interior of the building, but when Linus tells the usher he's a friend of one of the contestants, they are shown going inside from the exterior.
Continuity mistake: When Linus is in Charlie's bedroom towards the end of the film, you can see there is nothing next to the side of Charlie's bed, but when Linus leaves the room, Charlie's shoes and a sock have appeared.
Linus Van Pelt: This blanket is a necessity. It keeps me from cracking up. It may be regarded as a spiritual tourniquet. Without it, I'd be nothing, a ship without a rudder.
Linus Van Pelt: Well, I can understand how you feel. You worked hard, studying for the spelling bee, and I suppose you feel you let everyone down, and you made a fool of yourself and everything. But did you notice something, Charlie Brown?
Charlie Brown: What's that?
Linus Van Pelt: The world didn't come to an end.