When the heavenly whippet looks in Charlie's records, his mother and father are named "Loni" and "Burt", and look like canine versions of Loni Anderson and Burt Reynolds (who were together at the time.) Loni also appears in the film as one of Charlie's "close friends".
Don Bluth's birthday is also September 13, 1937. The idea that every human year is seven dog years is a myth — Charlie is about 25. Even though he seems older.
Celebrity Voice Actor: As well as Burt Reynolds voicing Charlie, the German dub has him voiced by the equally rascally Harald Juhnke.
Executive Meddling: We were originally going to get to see Charlie's body flying off the pier (a rare example of a meddling executive making a good call). Interestingly, many book adaptations of Don Bluth films include unused artwork; ergo, the tie-in book for this film showed a very clear silhouette of Charlie's body flying alongside the car...
Burt Reynolds (voice of Charlie) stated once that there was supposed to be some swearing in the film, and he distinctly recalls recording cuss words in his dialogue. All of it was removed to make the film more appropriate for children.
Name's the Same: Invoked. The title came from a book Don Bluth's teacher had read to him when he was a child. It was an anthology of stories about a noir-style dog detective. Bluth only remembered the title and looked it up years later when he became a filmmaker, but decided that he didn't like the story and based an entirely new one off of the title.
Otherwise averted in the entire series, where many of the characters are played by professional singers.
Subverted, considering the fact that Burt Reynolds, Dom DeLuise, Ernest Borgnine, and Charles Nelson Reilly all get songs over the course of the series. It seems that the one thing each installment had in common was giving songs to actors who couldn't sing professionally.
The Other Darrin: Save for Dom DeLuise and Charles Nelson Reily as Itchy and Killer, respectively, none of the actors from the first film are in the sequel or TV show.
Precision F-Strike: While recording, Burt Reynolds had come up with this "dog voice" for Charlie that he thought had sounded cute, but that both Don Bluth and Dom DeLuise both didn't like. Burt had insisted on it, but Dom finally knocked some sense into him and told him, "Burt, don't be an asshole.", and Burt decided to use his normal voice from then on.
Troubled Production: The sequel, according to the directors, was originally animated in Dublin, Ireland (where Bluth's original studio, which produced the first film, used to take place before that). But then, after Screen Animation Ireland, the Dublin studio in charge of the animation, shut its doors, the animation has to be outsourced to several studios in countries like Taiwan, Korea, Canada, and Denmark in order for the film to meet up the deadline.
Wag the Director: Burt Reynolds and Dom DeLuise, who had developed a repertoire with one another after starring in several movies together, insisted that Don Bluth leave the room during recording sessions so that they could improvise off one another better, to Bluth's chagrin.