“If you’re gonna try to get an audience to understand that you want to alter time travel rules.
That’s why we literally had to invoke Back to the Future in the movie at several points, so that we could say to people, ‘Alright, these are different rules than Back to the Future.'”
The hour-long discussion shed a great deal of light on the themes of time travel rules that connected the two blockbusters, which also necessitated name-dropping Back to the Future in the superhero ensemble feature.
That scene in Avengers: Endgame where they’re sitting around and talking about time travel, I understand that when they first previewed the movie, [it] didn’t have that scene in it.