(up) in the air vs unfulfilled

(up) in the air

unfulfilled

adj
  • Lacking fulfillment; marked by a feeling of failure to achieve goals or desires. 

  • Not yet provided as promised, particularly with respect to a contract or an order for a supply of something. 

How often have the words (up) in the air and unfulfilled occurred in a corpus of books? (source: Google Ngram Viewer )