Once in a while I'll get on a plane and there will be a built in phone on the back of every headrest. It will have a credit card scanner attached and an onscreen instructional demo will tell you that you can call anyone while the plane is in flight for the low price of $6 per minute. In all of my life I have never seen or heard a human being make a phone call using one of these phones. I suspect that's why they're not put on new planes. Boarding a plane and seeing the phones is unsettling to me. It's like seeing ashtrays built into the armrests. You think, "Good god, how long has this plane been in constant service?"