airbus vs hot-air balloon

airbus

noun
  • A subsonic jet airliner, especially a wide-bodied one. 

hot-air balloon

noun
  • A balloon-shaped aircraft whose bag is inflated with hot air; it carries passengers and crew in a gondola slung underneath. 

How often have the words airbus and hot-air balloon occurred in a corpus of books? (source: Google Ngram Viewer )