All characters are based upon circles and rectangles, except for the villains who are triangles.
The font used for the numbers on Carl's alarm clock is the "Chicago" font, one of the first fonts designed for the Macintosh. Steve Jobs, former Pixar CEO, also spearheaded the original Macintosh project at Apple.
If Carl's house was approximately 1600 square feet, and the average house weighs between 60-100 pounds per square foot, it weighs 120,000 pounds. If the average helium balloon can carry .009 pounds (or 4.63 grams), it would take 12,658,392 balloons to lift his house off the ground. (20,622 balloons appear on the house when it first lifts off.)
Russell is Pixar's first Japanese/Asian-American character voiced by an Asian-American actor, Jordan Nagai.
During pre-production of the film, director Pete Docter looked up to Disney veteran animators Frank Thomas, Ollie Johnston, and Joe Grant for inspiration. Docter stated that the film reflects the friendship he shared with these three talented animators before their passing as well as wanting to learn what they went through during their years working for Walt Disney and soon after.
Very first animated film, as well as the first 3D film, ever to open the Cannes Film Festival.
The Fenton's Ice Creamery featured in the movie actually exists and has two locations. One is in Oakland, CA on Piedmont Avenue and the other is in Vacaville, CA, and that is on East Monte Vista Avenue. Both locations are close to Pixar's headquarters in Emeryville, CA. There is also an express version of the creamery in Oakland International Airport to eat while you wait to catch a plane or if you just flew in. Fenton's did not have to pay to have it in there; Disney and Pixar put it in the film for free.
Dug's 'point' pose, where his entire tail, back, and head is in a perfectly straight line, is an homage to the identical pose that Mickey's dog, Pluto, often makes. Dug also shares a similar colour scheme to Pluto.
Pixar's second most commercially successful film after Finding Nemo.
Russell's Wilderness Explorer sash has several in-jokes and tributes. The most obvious is a Luxo Jr. ball. One badge has a hamburger with a candle in it. This is a nod to Merritt Bakery in Oakland - which creates cakes in that shape - a favorite hangout of director Pete Docter and producer Jonas Rivera. Another badge is a tribute to 2-D animation, showing a perforated paper that is used by 2D animators to line up their drawings correctly. He also has badges for First Aid and Second Aid, which may be a reference to a short on the Up website where Russell struggles to apply bandages to Carl. Yet another badge depicts a multicolored pinwheel - the "hang" icon of Apple's Mac OS X operating system, equivalent to the Windows hourglass icon. Several of these badges are shown in the credits. An additional tribute to Apple and Steve Jobs (former CEO of Pixar and still a primary shareholder) shows Russell trying to teach Carl how to use a computer.
The legendary singer Charles Aznavour performs the voice of Carl in the French version.
First film to be nominated for Academy Awards for both Best Picture and Best Animated Feature.
One of the construction machines reads L-R 1572, which is art director Lou Romano's birthday.
The only Best Picture nominee to have just 2 letters in the title.
Co-director/co-writer Bob Peterson (III) stated that Dug's line "I have just met you, and I love you," was inspired by a quote from a small child that he met when he was a camp counselor in the 1980s.
The first Pixar film since Finding Nemo not to be presented in the 2.35:1 aspect ratio.
The tepui (flat mountains) and waterfalls similar to Paradise Falls are actually found in Venezuela. The country's Angel Falls is the highest waterfall in the world.
The rifle that Charles Muntz uses is an 1874 Sharps, a very popular model with buffalo hunters of the American Wild West, and the procedure he uses to load, aim and fire the weapon is accurate. (His use of shot-shells in a long-range rifle, however, is questionable at best.)
Carl's summons notice has the number 94070 - the postcode of San Carlos - in which Brad Lewis, the producer was once the former mayor of the city.
When Carl is watching television, and is interrupted by Russell knocking at the door, he is watching a home shopping channel. This particular program has become a well-known blooper video of a pitchman making a gaff in which he describes a picture of a horse, except the picture he is describing is actually that of a moth.
The iconic, slightly out of perspective drawing of the house sitting by the falls is an homage to the style of Mary Blair, the artist credited with bringing the modern art look to Disney animation.
When a younger Charles Muntz speaks to a large audience that he will return with the beast alive, everyone is wearing a hat. What the viewer can't see, however, is that he is speaking to a literal "Sea of Hats". There are no people under those hats (DVD director's commentary).
First film produced by Pixar to be shown in 3D.
Inside the newly updated photo-book, one of the pictures of the couple is of them in a car, looking over their shoulders (Carl in the drivers). The pose they are in, as well as the car is a recreation of a famous ghost photo. In the picture, the man was posing for his brand new car, and in the passenger seat was the ghostly image of his mother.
The three main dog characters, Alpha, Beta and Gamma, as well as being named for the Ancient Greek alphabet, also reference three classes of workers in Aldous Huxley's novel Brave New World.
As per Pixar tradition, John Ratzenberger once again provides a voice in the movie, making him the only actor to do a voice in every Pixar film.
The second animated film to be nominated for an Academy Award for Best Picture. The first was Beauty and the Beast. However it is the first Disney/Pixar film to do so.
Not only are Carl and Ellie based on squares and circles, but objects around them are based on their shapes, like their chairs and picture frames. When they both appear in a photograph, the frame is both circle and square.
In June 2009, 10-year-old Colby Curtin from Huntington Beach, California, was suffering from the final stages of terminal vascular cancer. Her dying wish was to live long enough to see Up. Unfortunately, Colby was too sick to leave home and her family feared she would die without seeing the film. A family friend contacted Pixar, and a private screening was arranged for Colby. The company flew an employee with a DVD copy of "Up", along with some tie-in merchandise from the film. Colby couldn't see the screen because the pain kept her eyes closed, so her mother gave her a play-by-play of the film. Seven hours after viewing the film, Colby passed away.
On the DVD cover and in commercials, the dogs appear to be flying Curtiss F9C-2 Sparrowhawk airship-launched fighters. US Navy airships such as the Macon and the Akron based at Moffet Naval Airstation between the first and second World Wars were actually designed to carry and launch these fighters.
The first Michael Giacchino-scored Pixar film not directed by Brad Bird.
A code title used during production was "Helium".
The term 'A113' is the number of the courtroom, and can be found on the gold sign Carl sits next to while waiting to be called (Courtroom A113). A113 is a frequent Pixar in-joke based on one of the room numbers for the animation program at Cal Arts.
Film debut of Jordan Nagai, who voices Russell. Originally, his older brother Hunter was auditioning for the part, and Nagai simply came along with him. About 400 children had showed up for the auditions, but Nagai stood out because he would not stop talking. Director Pete Docter later said that "as soon as Jordan's voice came on we started smiling because he is appealing and innocent and cute and different from what I was initially thinking."
Pete Docter, the director, provided most of Kevin's vocalizations.
Alpha's deep voice has only 4 lines. The rest of Alpha's lines are spoken with his squeaky voice.
On the official movie website, there is a video clip titled "Ditch 'Em". The same scene in the film has music playing, while the clip on the site has only voices and sound effects.
SPOILER: WILHELM SCREAM: As the dogs fall off the cliff into the river below while chasing Carl, Russell, Kevin, and Dug.
SPOILER: All of the dogs except for Dug are named after letters of the Greek alphabet (Alpha, Beta, Gamma, etc) although this could relate to rankings in a dog pack, where the lead male is known as the Alpha, then Beta and so on. This is supported by the fact that when Dug puts Alpha in the Cone of Shame, all the other dogs begin referring to Dug as Alpha. The voices of both Dug and Alpha are performed by the same actor, Bob Peterson (III).
SPOILER: Carl and Russell's hometown at the end is Oakland. We see Oakland landmarks Fenton's Creamery and the Fox Oakland Theatre (showing Star Wars: Episode IV - A New Hope).
SPOILER: When Russell flies past the airship using his balloons and the leaf blower, we briefly see several of Charles Muntz's dogs playing poker at a card table. This is a tribute to the famous "Dogs Playing Poker" series of paintings by Cassius Marcellus Coolidge.
SPOILER: The villain Charles Muntz is named after Charles Mintz, the Universal Pictures executive who in 1928 stole Walt Disney's production rights to his highly-successful "Oswald the Lucky Rabbit" cartoon series. This led Walt Disney to create Mickey Mouse, who soon eclipsed Oswald in popularity.