The movie takes place between Seasons 4 and 5 of the original show.
This is Dave Needham's directorial debut after serving as a member of the art department & as an art director in several animated projects.
Chris Savino, creator of the original series, wanted the film to take place at the Loud family's house, with there being a scene in which the house exploded. He also wanted the film to not be considered canon. Since he was fired from Nickelodeon in 2017, he had no involvement in the film's production.
Chris Savino wanted to put the concept of the Loud family traveling to Scotland to meet their relatives into the original series. While he approved of this concept carrying over into the film, he did not like how the film introduced fantasy elements into the franchise's universe, since the original series does not have real dragons in it.
The film was originally planned to be released in theaters in the year 2020 until the plan was changed to let the film be released on Netflix in 2021 due to the ongoing of the COVID-19 pandemic.