Final answer:
The two biggest killers of soldiers in army aircraft have been enemy fire, including aerial combat and anti-aircraft defenses, and accidents such as mechanical failures or human error during combat operations.
Step-by-step explanation:
The two biggest killers of soldiers in army aircraft during combat operations have historically been enemy fire, including anti-aircraft artillery and missiles, and accidents, which often include crashes resulting from mechanical failure or human error.
Enemy fire was a significant threat to aircraft and their crews, as seen in World War II with the development of ace pilots and the fierce aerial dogfights. Anti-aircraft strategies and the use of military aviation advancements like radar also posed deadly risks for aircrews.
Additionally, accidents have been a serious and recurring danger in military aviation. Incidents like the British Lancaster bomber that caught fire in 1944 or the B-66 bomber missions during Operation Rolling Thunder illustrate the very real dangers of mechanical failures and the risks of combat flying.