Well, hopefully these will put this to rest:
Definitions of Aircraft on the Web:
means any vehicle capable of sustained air travel above treetop heights.
www.complianceregs.com/40cfr/ChapterI/subU/Part1068/1068-30.html
a conveyance by which human beings can rise into and/or travel through the atmosphere. Aircraft can be classified into those whose lifting power derives from aerostatic processes (buoyancy) as well as those rising under aerodynamic conditions (use of a static or moving airfoil and by those which ...
www.grazian-archive.com/quantavolution/Encyclopedia/encqnt5.htm
a vehicle for traveling through air.
www.cat.pinellas.k12.fl.us/ISTF/2006_2007/06-1450/Glossary.html
means a device that is used or intended to be used for flight in the air.
www.consistentformulations.com/Glossary.htm
includes a balloon.
scaleplus.law.gov.au/html/pasteact/2/3021/0/PA000110.htm
a vehicle that can fly
wordnet.princeton.edu/perl/webwn
An aircraft is any vehicle or craft capable of atmospheric flight.
en.wikipedia.org/wiki/Aircraft
means any machine that can derive support in the atmosphere from the reactions of the air otherwise than by the reactions of the air against the surface of the earth (Civil Aviation Act 1990):
www.ew.govt.nz/policyandplans/navigation/safety2006/bylaw1.3.htm
Now, if we want to start breaking the 'aircraft' catagory down into airplanes, helicopters, balloons, etc, that's a whole different thing.
