Nap-Of-the-Earth (abbreviated NOE) is a type of very low-altitude flight course used by military aircraft to avoid enemy detection and attack in a high-threat environment.

„Of things that exist, some exist by nature, some from other causes. By nature the animals and their parts exist, and the plants and the simple bodies (earth, fire, air, water) – for we say that these and the like exist by nature.
All the things mentioned plainly differ from things which are not constituted by nature. For each of them has within itself a principle of motion and of stationariness (in respect of place, or of growth and decrease, or by way of alteration). On the other hand, a bed and a coat and anything else of that sort, qua receiving these designations – i.e. in so far as they are products of art – have no innate impulse to change. But in so far as they happen to be composed of stone or of earth or of a mixture of the two, they do have such an impulse, and just to that extent – which seems to indicate that nature is a principle or cause of being moved and of being at rest in that to which it belongs primarily, in virtue of itself and not accidentally.”
—– Quote from Aristotle’s Physics, Book II translated by R. P. Hardie and R. K. Gaye from The Complete Works Of Aristotle, Jonathan Barnes (ed.), Princeton U. Press, 1984.