Wow - 61 to 61 votes.
It's aeroplane, but "airplane" is fine too (albeit an Americanisation).
I see it as "Aeroplane" because planes are vehicles that exploit aerodynamics in order to achieve flight, air is just the medium they use for transport.
For instance:
"I drive a car" as opposed to "I drive a motorcar" or "I drive a road car".
"I fly in a plane" as opposed to "I fly in an aeroplane" or "I fly in an airplane".
But I find myself calling them planes a lot of the time.
It's aeroplane, but "airplane" is fine too (albeit an Americanisation).
I see it as "Aeroplane" because planes are vehicles that exploit aerodynamics in order to achieve flight, air is just the medium they use for transport.
For instance:
"I drive a car" as opposed to "I drive a motorcar" or "I drive a road car".
"I fly in a plane" as opposed to "I fly in an aeroplane" or "I fly in an airplane".
But I find myself calling them planes a lot of the time.