Final answer:
The parallel structure of these lines emphasizes the pilot's lack of emotional attachment to both his enemies and his allies.
Step-by-step explanation:
The parallel structure of these lines emphasizes that the pilot does not have much emotion for his enemies or his countrymen. By stating that he does not hate those he fights and does not love those he guards, the pilot is showing a lack of emotional attachment to both sides. The parallelism highlights this lack of emotion and suggests that the pilot is detached and impartial in his role as a fighter pilot.