Flight of Dragons (1982)
The Flight of Dragons is a 1982 animated film produced by Jules Bass and Arthur Rankin, Jr. and loosely combining the speculative natural history book of the same name (1979) by Peter Dickinson with the novel The Dragon and the George (1976) by Gordon R. Dickson.
The film centres upon a quest undertaken to stop an evil wizard who plans to rule the world by dark magic. A major theme within the story is the question of whether science and magic can co-exist. This is told mostly through the experience of character Peter Dickinson, drawn from the 20th Century into the magical realm (well, his own anyway). Is it quite often that a writer will get "drawn into their own work", just not quite like this, at least not ALL the time.
"The Dragon and the George" (one of the sub plots of this film) is longer told by this movie's companion piece "The Magic Sword" (which is more live action than animated, though not wholly "real live action").