After Charlie Brown becomes popular, the kids struggle over who gets his attention. Shermy (who has not appeared in the movie to this point) grabs his arm and says, "I saw him first!" In the first Peanuts strip printed, Charlie Brown walks by and Shermy is the first character to see him.
Various steps were taken with the animation to emulate the original look and feel of the comics and the previous animated specials. The characters are animated in a more limited manner. Also, the trees and other foliage in the background are static and never billow or sway in the wind.
Charles Schulz wanted to call his comic strip "Charlie Brown" (it had started out as "Good Ol' Charlie Brown"), but the editors were worried about legal action from people who had that name. It started publication as "Lil' Folks", but because that was the original title of someone else's strip, his syndicate forced the title "Peanuts" on him. He hated the title (partly because it made people assume the character's name was Peanut) and didn't use it in any of the specials or movies, which were titled "Charlie Brown" or "Snoopy". This is the first "Peanuts" feature to carry that title.
The Little Red-Haired Girl is number four on the list of student's rankings on the standardized test, and her name is indicated as "Heather Wold". "Heather" was the name given to the Little Red-Haired Girl in It's Your First Kiss, Charlie Brown (1977). Donna Wold was named after Charles M. Schulz's real-life red-haired girlfriend, who turned down his marriage proposal in 1950 (the same year the comic strip began) and upon whom the character in "Peanuts" was based. (However, Wold and Schulz remained friends until Schulz's death in 2000.)
When Snoopy enters his dog house to fetch the instructions in order to help Charlie Brown learn to dance, he throws a bunch of stuff out. Amongst those, is the painting "Starry Night", by Vincent van Gogh. This is a reference to a running gag in the comic strips, when Snoopy is mentioned to owning a Van Gogh (though the painting is never seen).
While the World War I Flying Ace is struggling to return to his airfield, he is briefly shown sporting a wiry mustache as he is crawling through the desert. This is a reference to Snoopy's brother Spike, who was named after Charles Schulz' childhood dog and appeared infrequently in the comics. Spike wore the same mustache and lived in the desert country near Needles, California.
The Beagle Scouts, Snoopy's bird friends, who are all the same species as Woodstock, appear in this movie as the pit crew for Snoopy's plane in the World War I Flying Ace sequences. The birds are named Conrad, Bill, Olivier, and Harriet. In the comics, Harriet is generally portrayed as the toughest, while Olivier (likely the bird who appears to mess up constantly in the movie) is the dumbest.
Charlie Brown hands Patty and Violet a comic book with Spark Plug the Horse from the comic strip "Barney Google and Snuffy Smith" on the cover. Peanuts creator Charles M. Schulz's nickname was "Sparky" after this character.
Snoopy's siblings, Andy, Olaf, Marbles, Spike, and Belle, appear in the mid-credits scene. Two additional siblings, Molly and Rover, were created for the televised specials, but not by Charles M. Schulz, and are omitted from the scene.
On the back of the "Spark Plug" comic book Charlie Brown recommends to Patty and Violet, a "Lil' Folks" panel can be briefly seen with Patty and Shermy. "Li'l Folks" was a single-panel comic strip drawn by Charles M. Schulz from 1947 to 1950, and a precursor to the "Peanuts" strip.
There is a series of numbers on the test rank list for Charlie Brown's class, 555 95472, which is actually the name of one of Charlie Brown's classmates. 5 (as he called himself) first appeared in the Peanuts comic strip from September 30 to October 4, 1963. He has two little sisters, 3 and 4.
Charlie Brown's attempt to write a book report on Leo Tolstoy's "War and Peace" was also a plot point in the 1986 special Happy New Year, Charlie Brown (1986). Unlike this movie, in which Charlie's report is supposedly a well-written analysis, in the special, he received a D-. "War and Peace" was Charles Schulz' favorite novel.
In the promotion of this movie, there were specific reassurances to the property's fans that its score would include compositions of the musician most famous for his music for the property, Vince Guaraldi, where appropriate. The music can be heard in numerous sections, such as the opening skating pond scene that includes "Skating" and "Linus and Lucy".
On the list of test results, the names Violet Gray and Patricia Reichardt appear. These are the last names of Violet and Peppermint Patty in the comic strip, though they were used only once and twice in fifty years, respectively.
The trivia item below may give away important plot points.
When Charlie Brown erroneously finds that he got a perfect score, Peppermint Patty's test score of "65" can be seen at the bottom at number fourteen. This is not only Charlie Brown's real score on the test, but also alludes to the comic strip's 65th anniversary.