"Nana" was a Newfoundland, a breed particularly good with children, not a St. Bernard as used in the film. J.M. Barrie modeled Nana after his own dog, a Landseer Newfoundland. These dogs were very popular in Victorian England and were actually used to supervise children.
"Jas." is a standard abbreviation for the name James which is why the sign on Captain Hook's cabin door reads "Capt. Jas. Hook". This is taken directly from the book. It is not, as many viewers assume, a reference to Jason Isaacs.
According to Carsen Gray, when she's speaking to Hook, what she's saying is Iroquois for "You are the life-stealer. You are evil. You smell bad. You smell of bear-poop. You are many moons old and ugly."
Liam Aiken supposedly was set for an audition for the role of Peter Pan, however a few days before the audition producers found out that Aiken was only 12 at the time. The producers were looking for a young actor aged between 14-17.
An alternate, extended ending based on Barrie's epilogue is featured on the DVD, but with unfinished special effects and no music. In this version, Peter returns to the London house years later, finding an adult Wendy. He is deeply hurt when she tells him she has grown up, and walks over to her own daughter, asleep in bed. His sobbing awakes the little girl, and she introduces herself as Jane. Peter grins excitedly at Wendy, and with her mother's permission, Jane flies away with Peter to Neverland as Wendy watches them through the window.
Finding Neverland (2004), a film about J. M. Barrie and the creation of Peter Pan, was originally scheduled to be released in 2003, but the producers of this film - who held the screen rights to the story - refused permission for that film to use scenes from the play unless its release was delayed until the following year.
After the script was written, Stephen Cox, Chief Press Officer for Great Ormond Street Hospital for Children NHS Trust, gave the hospital's approval, saying, "We have read the script by P.J. Hogan and Michael Goldenberg and are delighted to report that we feel that it is in keeping with the original work whilst communicating to an audience with modern sensibilities."
A complex harness was built to send the live-action actors rotating and gliding through the air for the flight sequences. They were then composited into the shots of London and Never Land, although they are sometimes replaced with computer-generated figures.