Free range children!
Gen X was truly the last one to be given that kind of independence on a wide scale. My late older brother was a little less than four years older than me (born Dec 1980; me Nov 1984), but he went around town by himself as a kid in the early 1980s, and my parents were totally cool with it. When I came around, the Adam Walsh case had changed everything, and letting kids go around was no longer seen as a good thing, so I never had any time completely unsupervised. I think this is probably the biggest difference between how Gen X and Millennials were raised.