Which navigation aid automatically compensates for the effects of wind?

The correct choice is RNAV. This system utilizes satellite navigation and ground-based references to provide precise positioning and guidance. One of the advantages of RNAV is its ability to calculate the most efficient flight path, while also accounting for the wind's effect on the aircraft's trajectory. By incorporating data such as wind direction and speed, RNAV helps pilots maintain their desired course, ensuring that they can efficiently reach their destination even when faced with varying wind conditions.

VOR (VHF Omnidirectional Range), while an essential navigation aid, does not inherently compensate for wind. Instead, it provides directional guidance that the pilot must interpret in light of external conditions. Similarly, an altimeter measures altitude based on atmospheric pressure but does not involve navigation compensation, and DME (Distance Measuring Equipment) helps determine distance but does not adjust for wind effects either. Thus, RNAV is the navigation aid that automatically compensates for wind, facilitating more accurate navigation.