aeroplane vs air ship

aeroplane

verb
  • To transport by aeroplane. 

  • To fly in an aeroplane. 

noun
  • Any of various nymphalid butterflies, of various genera, having a slow gliding flight. Also called planes. 

  • Synonym of airplane. A powered heavier-than-air aircraft with fixed wings. 

air ship

verb
  • To transport (goods) by air. 

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