If your name is Barry Allen and you've been gifted with super speed after being struck by lightning, then it's mandatory that you fight crime while wearing a red costume. Ezra Miller's version of The Flash did just that briefly in Suicide Squad and fully in Justice League, because even though he was still new to the superhero game, he was still properly equipped when it came time to battle Steppenwolf and his Parademon army. As it turns out, though, there were originally plans for Flash to receive a second costume that was imbued with "Wayne tech" at the end of Justice League, but director Zack Snyder ultimately decided he didn't want to interfere with whatever the director for the Scarlet Speedster's solo movie wanted to do. In Snyder's words:
I wanted to give the Flash solo film director a chance to put his or her spin on it so no more a Concept.
Continuing to share details about his time in the DC Extended Universe on Vero, Zack Snyder posted a picture of Ezra Miller's first Flash costume test, and afterwards he touched upon how we would have seen this version of Barry Allen be given a new and enhanced suit once Justice League's main action wrapped up, only to scrap that idea. While I am intrigued by what Snyder and his team could have come up with, I can't fault Snyder for not wanting to step on the toes of whoever was hired to helm Flash's movie. Superhero costume changes between movies are quite frequent, but at least now directors John Francis Daley and Jonathan Goldstein have the freedom to either commission someone to design a new costume for their movie or stick with the one he's already wearing. And hey, Justice League still delivered a costume change of sorts at the end, as Cyborg's robotic body altered itself to more closely resemble how he looks in the comics.
If you think about, technically the traditional Flash suit is the second costume Ezra Allen's Barry Allen has worn, because when the future Barry briefly appeared during Batman v Superman: Dawn of Justice after Bruce Wayne's Knightmare, he was wearing a suit that was radically different from his usual garb. As for Flash's current suit, Barry made it from the same composite material that NASA uses to protect its spaceships from burning up during reentry. After all, when you're running at such incredible speeds, you don't want your threads to catch on fire during a mission.
At this point, there's little we know about The Flash's upcoming movie other than Ezra Miller will obviously reprise the speedy protagonist and Kiersey Clemons will finally debut as Iris West. Last year at San Diego Comic-Con, it was announced that the movie's title was Flashpoint, meaning it would adapt the 2011 storyline of the same name, but it's recently been rumored that's no longer happening. We also have yet to learn when Flash's solo movie will race into theaters, so stay tuned to CinemaBlend for that update and other major developments.