The Epilogue at the End...

Where we see what the members of the League are up to after they go their separate ways. I'm curious about Superman. When he was shown, you see him look up in the sky & then find a place to change & go do whatever, but what was it that he saw in the sky? The bat signal? It's the only thing I can think of.

Maybe Bruce is lending it to him also, so he can be alerted when somethings going on, I don't know, but that's the only conclusion I can reach. Anyone else think this too?