In a post-Justice League landscape, the biggest heroes of the DCEU have finally assembled to form an iconic team. That being said, the Justice League heroes all have their own solo movies on the agenda, with Aquaman next on deck. That has left many to wonder how the film will connect to other heroes in the DCEU lore, but in a recent interview, director James Wan admitted that he opted not to include the other DC heroes in Aquaman because he wanted to keep the story clean and focus on Arthur Curry. Wan said:
I wanted to keep the story to the world of Aquaman and not have to worry about what other characters are doing in their films and how that would affect us. I just thought the simplest way was to keep it clean --- keep it simple and let it be an Aquaman story.
We have already seen Arthur Curry operate with other heroes, so it makes sense to want to focus solely on his own exploits this time around. As James Wan explained in his recent interview with EW, he wanted to keep things "clean" and distill the Aquaman story down to the simplest version of Arthur. That means moving away from guys like Batman and The Flash, which frees up on-screen real estate for characters like Mera, Vulko and Black Manta.
This is not something that other DC movies have even had to worry about in recent years. Man of Steel was the first installment in the DCEU, and many of the heroes were either in hiding or unable to help Superman during his battle against General Zod. Then there's something like Wonder Woman, which took place long before the arrival of Superman or the birth of Bruce Wayne. Aquaman is the first post-Justice League DCEU movie, so DC now has to truly contend with the questions of why other DC heroes don't pop in to lend a hand.
Of course, none of this means that we won't get some references to other DC heroes. Even if the rest of the Justice League doesn't show up, it's still entirely possible that we could hear some references to other DC icons or have Arthur drop a hint towards his teammates -- such as how Ant-Man and The Wasp referenced Captain America: Civil War without showing the other heroes. All we know for sure is that Batman won't drop by Atlantis to throw a Batarang at some bad guys.