I'm playing the new Lego Batman 3, and while everyone is outside of the Justice League Space Station, everyone is either wearing protective suits (Batman and Robin), or is already known to be able to survive in space (Superman, Green Lantern, Cyborg) except for The Flash.
I'm not up to speed on my DC comics, so can Flash really breathe in outer space? Is his cellular regeneration enough to keep him from dying? Or is this another permutation of the Speed Aura "protective bubble"?
Flash has never been demonstrated as being able to breathe in space, or to hold his breath for superhuman lengths of time.
His 'powers and abilities' section on Wikipedia doesn't mention anything about it, though it does mention that he has the ability to generate a field around himself that protects him and his clothes from air friction.
Most likely, this was simply an oversight. Batman/Robin frequently have costume changes, and part of the 'always prepared' reputation Batman has (which I expect the Lego games would play up on) could easily include a space suit.
In short, no, no one from the Flash family has been shown to be able to avoid the issues caused by low-pressure, low-oxygen environments such as space.
As a simple aside, Batman doesn't really need the suit:
I can make a case for a Flash capable of utilizing the Speed Force, being able to survive in the vacuum of space.
One of the Flash's powers allows him to become intangible to matter and able to ignore his environment. This power becomes active when he starts moving faster than the speed of sound.
Why the speed of sound? In atmosphere, the Flash's speed soon becomes problematic as distances diminish through the use of his fantastic speeds (i.e. 600 miles per hour becomes 1 mile per second!) At slower speeds his prioperception (personal awareness of his physical body in relationship to his surroundings) he can pay attention to his environment and dodge things he approaches, but once he moves at high mach speeds or low percentages of the speed of light, being intangible is the safest approach.
Imagine what happens when he approaches 1% the speed of light (6,706,166.29 miles per hour, 111,769.43 miles per second or the ability to circle the globe several times in a single second).
While the Speed Force supposedly protects the environment from him, what protects him from the environment?
His intangibility. As he approaches the speed of light, under normal physics, objects grow heavier as they approach the speed of light. Not the Flash. Why?
Because he is becoming more like light and less like matter. The faster he goes, the more he behaves like a beam of electromagnetic energy. Including becoming and remaining intangibly out of phase and safe from harm.
From Flash 109, one of the earliest uses of his molecular intangibility.
There may be a time limit to how long he could do this but I have not seen him have any difficulty maintaining his intangibility. In Kingdom Come, the Flash has become a form of omnipresent energy where "flesh and blood... give way to... energy"...
During Wally West's run as the Flash, approached the speed of light and the speed force so often he became a being composed of pure energy. Again, not saying Flash must be portrayed that way, but certainly there is ample precedent for saying Flash is an energy being and not subject to the ills of space. Near the end of the series, Wally West approached the speed of light so often he became a being composed of pure energy.
Perhaps the implication is that he is holding his breath for, say, 5/6 of the time, then phasing inside and taking a breath for the other 1/6. His idle animation does include him zooming away every so often.
Yeah he ran across the universe faster than instant teleportation once, so it's established he can survive in space.
