The open secret around the comic book movie circle has been that Warner Bros. is planning a Justice League movie directed by Zack Snyder, and if they were trying to keep that secret they more than gave it away with Batman vs. Superman's casting. The rumors really kicked into overdrive last summer, but the studio has never officially said anything concrete about it until now, and along with it come some new details.
Warner Bros. has made it official to The Wall Street Journal that Justice League is indeed happening, and that Snyder is the guy who will be at the helm. Not really a surprise there since it has been his singular vision driving these films, and it will be interesting to see where that goes in the future. As the Batman vs. Superman casting has pretty much given away, the 2016 film will bridge right into Justice League....
"It will be a further expansion of this universe,” said Greg Silverman, president of worldwide production for WB. "’Superman vs Batman’ will lead into ‘Justice League.’”
The script, initially undertaken by Will Beall (Gangster Squad) before David Goyer took over, is still unfinished. There also seems to be some question on the release date. The WSJ report says 2018 is the target, but THR is saying 2017. Latino Review narrows it down to May 5th 2017, and since they were apparently correct in predicting Snyder would direct it back-to-back with Batman vs. Superman it may be a good idea to trust in their sources.
Whether it turns out to be '17 or '18, that should leave time for another film to be squeezed in. Around the time of last year's Comic-Con word spread that a Flash movie was on the way. Dwayne Johnson has been boasting about a DC project he's got coming up, which is presumed to be a Lobo film.
Also of note in WSJ's story is this about other DC Comics movies in development...
Warner Bros. has several other movies in development unconnected to the Justice League that are based on DC superheroes and fantasy and crime titles from its Vertigo line of genre comics, said Mr. Silverman and Toby Emmerich, president of Warner’s New Line Cinema label. They include “Shazam,” “Metal Men,” “100 Bullets,” and “Fables.”
Fables has been in development for years, and was once going to be a TV series until Once Upon a Time stole its thunder. Shazam has also been a rumored project, which at one time had none other than Dwayne Johnson pegged for the role of villain, Black Adam. We'll see where any of these films go, but I'd be surprised if Shazam is truly "unconnected" from the Justice League.