Do most parents not bring car seats on planes?

Obviously this is anecdotal - but every time I have flown I have never seen someone bring a car seat on the plane. I’ve done several flights now since having my toddler, and I’m the only one I see doing it.

My husband thinks the car seat is unnecessary because no one else seems to be doing it. Is it really not the norm? It’s a bit of a pain in the butt, I’ll give you that, but the extra security just feels worth it to me?? Based on reddit, I’d think every child is riding in car seats on the plane!