Is there an abstract word for the environment in which a vehicle can move?

Is there an abstract word for the environment in which a vehicle can move? References I am looking for a word (or short construct of words) that could be used to refer to things that a given vehicle could traverse: \"sky, land, water. etc.\" To give an analogue, I can refer to \"gasoline, diesel, electricity, rocket, etc.\" as \"fuels\" In my specific case, I can\'t use \"environment\" because it\'s being used to describe other things in the same work, and would become ambiguous.