I know that if you do knockback on a figure and he goes over a building they take 2 damage. Does this also apply if you knock a figure with flight off the edge or does their ability nullify the damage?

The new marvel FAQ on wizkids site just talked about this, there is a mention of clinging damage still applying, but i'm not too clear on what exactly that is.

flyers don't suffer the damage it's in the update @ the wizids website

Just to clarify about "clinging" damage. A flyer won't take the 2 points of damage if they are hit off the building but if there is a figure in the square that they would land in then the flyer stays on the building and takes 1 point of damage. It's in the FAQ where they explain it as the person being knocked back noticing the person below and straining themselves to "cling" to the roof.