Twords the last half of their down/damaged/burning time, when the fires begin smoldering, I'd like the smoke to act more as a low fog, engulfing the field or the corner of it that was damaged. I think it'd be cool, a little more realistic, add a level of dificulty to follow-up bombing and help disipate the enemy and cover uppers in an active runway vulch as the base comes back up. It's not like it would be impossible to keep vulching through it either, or for expereinced bombers to pinpoint their targets.