A high school friend of mine's father was an infantryman during WWII and Korea. Unlike most pilots, he witnessed the killing up close and personal. He once told me that he did kill a 12 year old who was sniping at his unit. He didn't know the sniper was 12 at the time but it wouldn't have mattered. When someone is shooting at you, he/she's a combatant regardless of age. He said it was terrible that he had to kill that child but war is a terrible thing.

Please don't take my comment about pilots as any sort of slam against your father. Lancaster duty was damned dangerous and he's fortunate to have survived the war. He and thousands like him rendered valuable service during the war.

I've known a lot of former WWII pilots. Many of the bomber pilots were deeply saddened at the death and destruction they wought in the war. They know their bombs didn't all land on military targets. The RAF/RCAF bombers were deliberately targeted against population centers for most of the war because they lacked the navigational accuracy to do precision night attacks at the time. Air Marshal Harris (head of Bomber Command) once said, "It takes 2 years to build a factory. It takes 20 years to grow a factory worker."

War is a terrible thing to be avoided whenever possible. Sometimes, it isn't possible to avoid war.