As far as I know, I've been on a plane only once in my life, and I was way too young to remember it. I was only one year old, and my parents obviously couldn't leave me behind. We went to California, mostly for my uncle's wedding (one of my mom's three brothers). My brother and my sister, both of whom are younger than me, have never been on a plane at all, but since I obviously don't remember that trip to California, I feel like the three of us have the same (lack of) experience.
Edit: My dad, on the other hand, has flown on a plane numerous times for business trips. At least a few times per year, but I've clearly lost count by now.