"Papa, do some jets have guns on them?"

My young son asked me quizzically, as he's wont to do. He was playing with his toy jet one minute, and the next, he was asking me if some jets have guns. I told him yes, and explained to him about fighter jets. Then, in all the innocence of childhood, he asked me why. "Why papa? Why do people put guns on some jets?" The question blindsided me. How do you explain that to a child? How do you explain that to anybody? I wasn't sure I really knew the answer, but I thought about it for a minute and the realization dawned on me: People put guns on jets because we can't communicate. If we are ever going to mature as a species/star-faring race we have a long way to go on the development of our communication skills.