I think if Mexico is handing out masks, then its airborne.
They're handing out masks because it can spread if someone coughs, sneezes, etc. And yes, that does mean that it's partially airborne, but it can only spread accouple of feet, from the person who has it. Along with that, they're just trying to take simple steps of making sure people don't get it, and these masks are probably not very difficult to supply.
It doesn't get carried cross country on an gust of wind.
IT'S IN OUR loving TORNADOES!!!