"As the crow flies" is an idiom describing the shortest, most direct straight-line distance between two points, ignoring obstacles like mountains, rivers, or winding roads. It contrasts with the actual travel distance, which is typically longer due to terrain detours.
Note: while crows don't always fly in perfectly straight lines, the phrase highlights a "beeline" path.
Etymology:
The meaning of the expression is attested from the early 19th century, and appeared in the Charles Dickens novel Oliver Twist
"We cut over the fields at the back with him between us – straight as the crow flies – through hedge and ditch."
Usage:
"The cities are 50 miles apart as the crow flies".
“Two places might be 5 miles apart as the crow flies, but 10 miles apart by car due to a winding road.”
- From Wiki +, with editing
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Don't think there's more explanation needed. But I found a short poem about a crow flying below (hopefully it won't put anyone out like a light 
)
My reading:
The Crow Flies
- by Dave Alan Walker
A single crow flies,
flies to free the soul
from the flesh of the one
who's been laid to rest
And to let that soul see
all that is beautiful
in a spirit world of
love and peace
