I'm especially confused because I thought the iPad Air and "standard" iPad were different generations of the same product family, and the Airs were called that

I'm especially confused because I thought the iPad Air and "standard" iPad were different generations of the same product family, and the Airs were called that because they were much thinner than earlier models. There's never been a (current-gen) "iPad" and "iPad Air" at the same time. But now there are, and based on how their web site organizes them it seems like they are considered different families.