NOE meaning in Military and Defence ?

Nap-of-the-earth (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.

During NOE flight, geographical features are used as cover, exploiting valleys and folds in the terrain by flying in, rather than over, them. This keeps below enemy air defence radar coverage, avoiding being silhouetted against the sky. Other, mostly older terms include "ground-hugging", "terrain masking", "flying under the radar" and "hedgehopping".