I'm in the process of writing a story (just for fun with my son) that takes place somewhere around 80-100 years after an end-of-the-world event. Right now, that event is some type of plague, but that part will be secondary to the story. The story is set around 2100 or so, with very few survivors. Villages have formed throughout the US, but for the most part, people are not entirely sure of what exists outside of their own village. For most people, each day consists of farming, foraging, and just trying to stay alive.
The story focuses on a twelve-year-old boy who decides to leave his village for one of two reasons, and I'm stuck on which one (if either) is more plausible, given the time that has passed since the plague/virus/disease.
The boy has spent the last year or so building a radio (after scavenging for parts, books, etc.). One day, he hears someone (or maybe a recording) on the radio. He wants to tell the others, but he knows they will not believe him. The boy's father went missing a few years prior (on a scavenging expedition), and although the boy does not think the two events-the radio transmission and his father disappearing-are connected, he decides to leave the village to at least find some answers.
The boy, while looking at the sky one night, (he's very interested in astronomy) is positive he saw some type of blinking lights in the distance. He does not yet know it, but those blinking lights were from a helicopter (or airplane). He again does not think that the lights have anything to do with his father, but he decides to leave to find out.
In terms of world building, I'm wondering if either of these would work. I've done some preliminary research on HAM radio, but I'm still not sure if such a scenario with the radio would he possible or likely. Likewise, with most (I'm thinking close to 99 percent) of the world's population gone, how long would it take for something like an airplane or helicopter to become functional again?
Thanks for any feedback!