Jason Colavito has an informative post on the “big-business-factual-data-be-damned” approach of Ancient Aliens. The early section of his post notes connections between ancient astronaut theory and pop-culture, specifically with respect to Marvel comics.
The connections between ancient astronaut worldview and the sort of science fiction of comic books are deep. The comic book worlds pre-date the work of Sitchin and von Daniken. As Jason notes, there are secure roots in the writings of Lovecraft and others, but the more “vulgar” genre of the comic book also plays a significant role in where ancient astronaut theory really gets its “data”.
I recommend to readers two works in this regard. The first is a popular work of non-fiction. The second is a scholarly work (Univ of Chicago Press). Both are fascinating. The second, naturally, is dense and a harder read.
Christopher Knowles, Our Gods Wear Spandex: The Secret History of Comic Book Heroes
Jeffrey Kripal, Mutants and Mystics: Science Fiction. Superhero Comics. and the Paranormal
One more work on the subject definitely deserves mention: Wiktor Stoczkowski’s Des Hommes, des dieux et des extraterrestres. Ethnologie d’une croyance moderne, Paris, Flammarion, 1999 (I don’t know of any English language edition, but the book was translated into Polish). It explores connections between ancient astronauts, popular literature of the first half of the XXth century, and the stories of the origins of human races and civilisations created in theosophic circles at the turn of the centuries and later. There are not only many borrowings between them (in every direction), but also numerous personal connections. It might be said without much exageration that there would be no literary genre later known as “science fiction” without an influx of ideas from occultist milieu.