Skyrim: Do dragons attack areas that you are not currently in?

No, game only generates things when you are in the region.

Exception to event put into the game which would just "change/create" things in other region which will do nothing until you are in the region.

Example.

Quest - Save house from fire in whiterun

The house in whiterun will be on fire when you get there.

So all in all, no.

Exception to planned events.

Which still only happens when your in the region.

im not really sure but i would have to guess yes because when your just traveling around you could find a village and leave but come back an hour later and then a dragon would be attacking it and killing people

I don't believe so. I think things only happen when you are in the actual area. The game shouldn't continue running other areas in the background.