My dad says I need to check to see if my flattened tire has a tube or is tubeless. He says he thinks my old ten-speed is tubeless so my bike is probably tubeless, especially if I've located (as I believe) a tear in my tire that's letting all the air out. He says if my bike had a tube in it, my tire wouldn't being going down because the tube really holds the air. But I figure that most tubeless tires would be on newer, sportier bikes to reduce weight or something. My bike is from 1974, give or take a year. Also, when I googled "tubeless bike tire vintage" all I got were results related to mountain bikes.
So what do you think--tube or tubeless?