Crossword puzzle clue "going without food as drones do"

Going without food as drones do?

Going, going, going

Answer to the riddle "What has rivers without water, forests without trees, and cities without houses?"

Warning sign at a train station's food court? (NOTE: The original sign, without my additions, actually exists. It's in Grand Central Terminal in NYC, on the lower level — the food court level. The sig

Where drones return

Protection by drones, say