I don't know about your definition. The term comes from a two-wheeled chariot it seems (though the etymology of that seems to be a word meaning "to run"). It's been used from everything from chariots, to train cars, to street cars, to automobiles. They all share two things in common. They're an enclosed container meant to carry things, and they've got wheels.

I don't think the wheel thing is fundamental to the definition anymore. Anything traveling on the ground is going to have wheels. The "flying" part let's you know how it travels, the car part informs you about the utility. I think it's perfectly clear what it means. What else should we call it that'd be more clear?