1
general::
In addition to the following idiom, Also see CASTLES IN THE AIR; LEAVE HANGING (IN THE AIR); NOSE IN THE AIR; UP IN THE AIR., 1. In circulation, in people's thoughts. For example, There's a rumor in the air that they're closing, or Christmas is in the air. [Second half of 1800s] Also see IN THE WIND. 2. See UP IN THE AIR. [Mid-1700s]
American Heritage Idioms