Okay. We seem to have been flying by the seat of our pants on this one. Here's my guess, based on nothing other than being absolutely sick of Tornadoes and Jaguars flying over my house at altitudes with negative signs in front of them:

If you look at a topographical map, the contour lines run reasonably close together, or at least trend together for any given geographical feature, like a hill or a valley between hills. If you think of corduroy, something similar applies. The ridges and valleys run close together. Assuming that nap of the earth flying involves flying at low level along contours, which it must usually do, there's your "nap".

How it came to be used as military jargon, heaven only knows. Just remember, "military intelligence" is an oxymoron!


The idiot also known as Capfka ...