Aeroplane or Jet Engine?

Most people will know the word aeroplane if i say it, but i could just say plne. But there's another version which is slightly different. Instead of a i r aeroplane, there's an old fashioned way of spelling it and saying it. And that's pronounced aeroplane with three syllables. So you can say aeroplane or you can say Aeroplane, but notice the difference spelling in each one.