From Star Wars: Episode IV - A New Hope
The battle station is heavily shielded and carries a firepower greater than half the star fleet. Its defenses are designed around a direct, large-scale assault. A small one-man fighter should be able to penetrate the outer defense.
Pardon me for asking, sir, but what good are snub fighters going to be against that?
Well, the Empire doesn't consider a small one-man fighter to be any threat, or they'd have a tighter defense. An analysis of the plans provided by Princess Leia has demonstrated a weakness in the battle station. But the approach will not be easy. You are required to maneuver straight down this trench and skim the surface to this point...