I don't think that's a correction. You are being more specific, but Lily is definitely "an unmanned aircraft or ship that can navigate autonomously"...which is what a drone is[1].
Since you have referenced dictionary.com, a very authentic source for tech terminology, I would like to argue why a plane is not called "vessel" in everyday usage?!
http://dictionary.reference.com/browse/vessel
It is annoying that everyone started calling Quadcopter a "drone", which is a very generic term. Flippin non-tech marketing peeps. -_-