Petrie is having a difficult time preparing for the Day of the Flyers, an important day for all of the flying residents of the Great Valley, when all of the young flyers must participate in a precise flying exhibition to prove that they are ready to fly with the adults. Always a nervous flyer, Petrie has even more trouble flying with his siblings in precise group formations. At the same time, a strange newcomer to the Great Valley has Littlefoot and his friends trying to help figure out just exactly what he is. Named Guido, a Microraptor, he is the strangest looking creature any of the Great Valley creatures has ever seen, especially since he has never seen another like himself. Cera is having her own troubles, as her grumpy father and his new mate, Tria, get ready to welcome a hatchling to the family. The hatchling's name is Tricia and Cera begins to slowly bond with her new sister.

All of these issues come together on the night before the Day of the Flyers, when Guido starts to figure out what he is. Guido begins sleep walking and Petrie and his friends follow him, inadvertently leading all of the gang on a perilous adventure into the Mysterious Beyond. In the Mysterious Beyond, Guido wakes up from sleep walking and accidentally wakes up a Spinosaurus which gives chase and tried to eat them. But Petrie, Guido, and the others defeat the Spinosaurus by trapping and wedging it between two rocks and they returned to the Great Valley.

As the Day of the Flyers arrives, Petrie and his siblings begin to participate. Following Guido's advice to be himself, Petrie's performs his own unique flying and inspires the other flyers to do the same. While watching and following the flyers, Tricia falls into a river and was carrying her straight to the waterfall. Guido, Petrie, and Petrie's siblings rescue her just in time but they accidentally drop her and Cera saves her before she lands in the river again. Tricia then says her first words, which is "Cera". The film ends with Cera and her family loving on Tricia while the other Dinosaurs watch in awe.

• Nick Price as Littlefoot
• Anndi McAfee as Cera
• Aria Curzon as Ducky
• Jeff Bennett as Petrie / Petrie's Sibling #2
• Rob Paulsen as Spike / Guido / Kosh
• Tress MacNeille as Petrie's Mother
• John Ingle as Topsy / Narrator
• Camryn Manheim as Tria
• Kenneth Mars as Grandpa Longneck / Parasaurolophus
• Nika Futterman as Petrie's Sibling #1 / Tricia
• Susan Blu as Petrie's Sibling #3

The project was announced in August 2005, along with The Land Before Time TV series, both set to debut in 2007.^[1] It was the first sequel in the series to be filmed in widescreen and the first to be filmed in the high-definition format, although the Region 1 DVD was in full screen (cropping the left and right of the image), though not pan and scan as the camera stays directly in the center of the image. However, the previous film The Land Before Time X: The Great Longneck Migration was matted to anamorphic widescreen on DVD in Israel. To help promote the film, the music video for the film's song Flip, Flap and Fly was shown during early theatrical screenings of Curious George, and was then released as part of the opening previews on the DVD release of that film and PollyWorld with the music video two times.

The Universal Studios website notes this film as a "tween film".

The same production team remains, with Charles Grosvenor as director and producer. It was produced by Universal Animation Studios and distributed by Universal Studios Home Entertainment.

This was the second film in the series to contain slow-motion; as Littlefoot jumps off the falling tree, he is very slow until he lands on the cliff.

Animation was provided by Wang Film and Cuckoo's Nest studios in Taiwan.

The film was released on DVD in the United States and Canada on February 27, 2007. Bonus features included a read-along, two sing-alongs, and two interactive games.^[2][3] On the same day, the film was also given a Walmart exclusive DVD 2-pack with a bonus DVD containing two episodes of The Land Before Time TV series to promote the Cartoon Network airing of the TV series in the United States.^[4]

The music score was composed by Michael Tavera and Kyle Kenneth Batter with additional music composed by Billy Martin. This was the second film in the series without James Horner's original score from the first film (the first was The Land Before Time X: The Great Longneck Migration), although Michael Tavera's older themes from the previous sequels can still be heard in this film.

All tracks are written by Michele Brourman and Amanda McBroom.

• List of animated feature-length films
• List of films featuring dinosaurs

• The Land Before Time XII: The Great Day of the Flyers at IMDb  
• The Land Before Time XII: The Great Day of the Flyers at AllMovie
• Official website
• The Land Before Time XII: The Great Day of the Flyers trailer