While doing press for the release of the Justice League movie, Jason Momoa confirms what just about everybody thought, which is that Clark Kent was actually saved by Aquaman in that oil rig scene from Man of Steel.
The scene in Man of Steel featured Henry Cavill as Clark Kent saving workers on an oil rig, but then it explodes. Clark is then shown underwater, but then the sound of whales can be heard!
Jason Momoa offers up that he spoke with Zack Snyder who confirms it is Aquaman that helped out Clark Kent and also that it connects to the Justice League movie: When Bruce Wayne goes to recruit Arthtur Curry, Aquaman tells Bruce Wayne that he has run into Superman before.
The Man of Steel Aquaman scene makes sense because we can guess that Aquaman became aware of the oil rig disaster and sent help, it's just so happens that Superman was there first!
Interestingly enough, a set image from Justice League almost looks like it could be from that Man of Steel oil rig scene as well.
Jason Momoa talks about the Aquaman Man of Steel Easter Egg and Justice League connection around the 4:55 mark:
Man of Steel Aquaman Easter Egg:
Justice League has a November 17, 2017 release directed by Zack Snyder, with the story by Chris Terrio and Zack Snyder, the screenplay by Chris Terrio and Joss Whedon, and stars Ben Affleck as Batman, Henry Cavill as Superman, Gal Gadot as Wonder Woman, Jason Momoa as Aquaman, Ezra Miller as The Flash, Ray Fisher as Cyborg, J.K. Simmons as Commissioner Gordon and Willem Dafoe an Atlantean, Nuidis Vulko.
Fueled by his restored faith in humanity and inspired by Superman’s selfless act, Bruce Wayne enlists the help of his newfound ally, Diana Prince, to face an even greater enemy. Together, Batman and Wonder Woman work quickly to find and recruit a team of metahumans to stand against this newly awakened threat. But despite the formation of this unprecedented league of heroes—Batman, Wonder Woman, Aquaman, Cyborg and The Flash—it may already be too late to save the planet from an assault of catastrophic proportions.