Why do riders swing the bike out sideways when jumping? When people do really big jumps on a bicycle or motorcycle, they'll swing the tail of the bike way out to the side once they've taken off. Then it rotates back under them by the time they land.





Do they do this just because it looks cool? Or do they have to do it for stability reasons?

EDIT: After hunting up a bicycle image of this effect, it's clear that it's a trick.
It's a trick -- it looks good on camera and would count for points accordant with degree-of-difficulty and "sticking the landing" at an adjudicated comp. The bike and rider become effectively parallel with their upright-riding stance; as opposed to perpendicular when in contact with the ground.

It's also a marketing cliche in biking. Like an "ollie" or a "kick-flip" on a skateboard - landing this grants credibility and implies talent, courage, maybe stupidity ... depends on the actual vs. perceived talent level. 

To be clear - cuz looks cool.