OH MY GOSH! LOL! I really wanted to know which countries used airplane and which used aeroplane, so I Googled it. I went to the comments section of a page and this is what I found...

Comment:
It makes more sense to say airplane because the contraption flies in the air.

Reply:
You do know what 'aero' means, right? Yours is a ridiculous argument.

BUUUUURRRRRNNNN!!!!! No offence to the person who wrote that. XD