air force vs military

air force

noun
  • A unit in the U.S. Air Force larger than a division but smaller than a command. 

  • A branch of the military mainly devoted to air warfare, as opposed to (land) army and navy. 

military

noun
  • Armed forces. 

adj
  • Relating to armies or ground forces. 

  • Relating to war. 

  • Characteristic of members of the armed forces. 

  • Relating to armed forces such as the army, marines, navy and air force (often as distinguished from civilians or police forces). 

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