Hmmmmm.....
<pedant mode on>
I was always taught that an aircraft was either an AEROPLANE or an AIRPLANE (for our transatlantic friends). I personally prefer the term aircraft, as it is both more descriptive and crosses the transatlantic language barrier fairly easily.
I have also always understood that a PLANE is a tool used by carpenters and joiners for the purpose of removing slivers of wood.
<pedant mode off>