The following post has spoilers for Inglorious Basterds and Once Upon a Time in Hollywood so proceed at your own discretion.
In the film Inglorious Basterds the heroes in a bloody and suicidal action murder the inner circle of the Nazi party including Hitler himself, presumably bring World War II to a premature close while in the current movie Once Upon a Time in Hollywood the cult followers of Charles Manson instead of murdering Sharon Tate and her houseguests attack her neighbors presumably launching Hollywood into a utterly novel sociological path.
Are these films with their fantastic premises and fairy tale ending popular examples of Alternative History fiction? Alternative History is that genre of speculative fiction which imagines how the world might have been different had history taken a different track than the one we know. For example what if the USA had lost its war of independence, or if WWI had not started? Harry Turtledove is today’s best practitioner of this art.
One the face of it this answer seems obvious, both of Tarantino’s film wildly diverge from actual history making those cinematic excursions truly an alternative to our own. However I think it require more than that. After Braveheart has loads of things wildly different from actual history and yet I have not heard anyone argue that it is an ‘alternative history.’
I believe an essential component of alternative history is an examination of what those differences mean to our understanding of the world. It is an examination of the consequencesof the change not just the change itself. In both films the story ends with the change, we never see what that means for the wider world. How does Hitler dying in 1944 change the Cold War, with Tate’s brutal murder how does film making change? We have no answer from the filmmaker, not even the hint of one. These are fairy tales, not alternative histories.
