To CLEAR THE AIR means to somehow resolve a difficult situation between people. It is especially used for talking openly about problems, or being patient and waiting for bad feelings to lessen.
“Sharon’s been ignoring me all week because of what I said to her, but we finally talked this morning and it really helped to clear the air.”
After a long and stressful few weeks, the team realized they needed to work together and have agreed on a plan of action. Needless to say, this has cleared the air and everyone feels much more positive.