Even airports are getting in on the echo-friendly push. Mowing grass is out at San Jose, Seattle, Boston, Nashville, Phoenix, Indianapolis airports.

The solution? Goats.

According to Wednesday’s story in USA Today, airports are planting more native plants and installing fewer grassy lawns, which require power mowing. These airports then use goats and sheep to keep their lawns manicured. So, on your trip home, if you spot a goat next to the runway, don’t worry, just wave. He’s supposed to be there.