hot-air balloon vs suitcase

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. 

suitcase

noun
  • A large (usually rectangular) piece of luggage used for carrying clothes, and sometimes suits, when travelling. 

verb
  • To smuggle in one's rectum. 

  • To trade using samples in a suitcase. 

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