In earlier versions of the movie, Batman used a unique motorcycle with anti-gravity technology to help him hover above the ground.
That said, director Zack Snyder eventually decided that Batman should use something a bit larger, with the ability to carry multiple inhabitants, per Ed Natividad’s explanation of the decision to Film Sketchr.
Developing a movie with Batman in it must feel like a gadget lover’s dream, and Justice League went through a series of different iterations and incarnations, which involved changing the tech used by Bruce Wayne in the fight against Steppenwolf.