Shazam! or Black Adam
Another two but somewhat unlikely options are the Shazam! and Black Adam movies. Both films' eponymous characters are tied to one another - and to the wizard Shazam, who chose both characters to be his successor at different points in time. Considering that Shazam (formerly known as Captain Marvel) is a longtime member of the Justice League and Black Adam is typically depicted as either a villain or an anti-hero, there's room for Superman to appear in either film, but in decidedly different roles.
The best choice would be for Cavill to appear in Black Adam. After all, the actor teased a team-up of sorts with star Dwayne Johnson last year, and both Superman and Black Adam have been known to fight each other on occasion in the comics. But considering that the Black Adam movie will likely depict Johnson's DC character as more of an anti-hero, the studio may not want to present Superman as some sort of antagonist, especially after they flirted with that already in Dawn of Justice.
A similar issue rears its head for Billy Batson. Although it would be interesting to see Shazam and Superman face off against each other, audiences may want Superman to fight alongside Shazam instead, especially if the film's story were to be based partly on the Superman/Shazam: First Thunder comic miniseries from the mid-2000s.
The least likely but still possible choice for Cavill's final flight as Superman is the Flashpoint movie. The Flash's solo film was originally slated to release in March 2018 but was later pulled from the schedule and replaced with Roar Uthaug's Tomb Raider reboot after the Scarlet Speedster's film suffered multiple hurdles behind-the-scenes. Director Seth Grahame-Smith exited the project in April 2016 due to creative differences with Warner Bros. and was quickly replaced by Rick Famuyiwa, who then left the film in October 2016 for similar reasons. Although the studio hasn't signed a director to The Flash movie yet, they revealed at SDCC 2017 that the movie will be titled Flashpoint.
The Flashpoint comic series follows Barry Allen as he travels back in time and prevents his mother's murder, thereby catapulting the DC Universe into an alternate timeline, named Flashpoint. A number of events are changed in that timeline, such as Bruce Wayne being murdered instead of his parents, with his father, Thomas Wayne (played by Jeffrey Dean Morgan in Batman V Superman), becoming Batman and his mother, Martha Wayne (Lauren Cohan), becoming the Joker. What's more, the Atlanteans and Amazons are at war with each other (something alluded to in Justice League), with Superman is being held by the U.S. government in a secret laboratory.
Superman's participation in Flashpoint is negligible - being relegated to fighting Enchantress (played by Cara Delevigne in Suicide Squad) - so it's unlikely that Cavill and Warner Bros. would choose that movie of all movies for his final go as the Last Son of Krypton - but anything's possible.
- Aquaman (2018) release date: Dec 21, 2018
- Wonder Woman 1984 (2020) release date: Jun 05, 2020
- Shazam! (2019) release date: Apr 05, 2019