Derecha la Flecha
We use this expression to imply that someone has to go straight ahead, by the shortest route, measured as a direct line connecting two points.
Birds fly in the air, where there are not any twists, detours, hills, rivers or any other obstacles to go around. A straight distance of one mile from one point to another might take five or more miles of real road trips. But in the air everything is straight forward. Most birds, like crows, just simply fly on a direct tour from an A to a B point.
Woman: Excuse me, Sir. Where is the nearest supermarket?
Man: Oh, it’s ten blocks ahead from here.
Woman: Do I have to turn left of right any place before?
Man: Oh, no! Just keep going straight; as the crow flies.