aviation vs paper aeroplane

aviation

noun
  • The art or science of making and flying aircraft. 

  • Flying, operating, or operation of aircraft. 

  • Industry that produces aircraft. 

  • A cocktail made with gin, maraschino liqueur, crème de violette and lemon juice 

  • aircraft 

paper aeroplane

noun
  • A toy aeroplane made by folding up a sheet of paper. 

How often have the words aviation and paper aeroplane occurred in a corpus of books? (source: Google Ngram Viewer )