As the crow flies
Definition 1 of 1
Pro Tip 1/3Geographic Distance
Used to describe the shortest path between two points on a map, not considering roads or obstacles. 
My school is about 5 miles away from my house as the crow flies.
Pro Tip 2/3Not Literal
It's not about actual crows flying; it's a figurative way to express distance. 
The lake is 2 miles from here as the crow flies, though there's no direct path.
Pro Tip 3/3Comparing Routes
Highlights the difference between direct distance and the actual travel distance. 
It's 30 miles as the crow flies to the city, but 40 miles when driving.