The dog in the movie is called Ripley (shown by the name on the doghouse), with the appearance close to that of the Xenomorph from Alien, el octavo pasajero (1979), and is obviously an homage to Ellen Ripley, the protagonist from the Alien franchise.
Dwayne Johnson's first animated film.
Even though many things on the alien planet are round in design, nothing has wheels. The Aztecs were one of the few ancient civilizations that hypothesized about alien life, and never used wheels.
The film was originally going to be titled "Planet One," until the owners of Planet One, which makes children's and teen TV programs in the United States, threatened to sue. The film's producers had no knowledge of the company's existence, and apologized. They then chose to call the movie "Planet 51" after Area 51, the supposed center of American UFO investigation.
With a budget of $70 million, this is the most expensive movie produced in Spain.