if the earth was flat, wouldn't those be the far away stars that are supposedly invisible due to haze?
They would, except there is no haze that high in the atmosphere. The thing is, there is a ton of haze in the bottom-most layer of the atmosphere (that cause ships to disappear), and there is not much haze over that. Most of the atmosphere actually has no haze, so most of the air the star light passes through is clean.