Interesting, mine used to be three. Even on longer drives there were people who'd argue the time thing, and make perfect sense. The only thing not mentioned in this argument is that when driving you are working. You have to stay alert and attentive. When flying you are just a piece of meat. Want to doze or have a drink or three, no problem.

But as time has passed I find my minimum has increased greatly. Part of it is influenced by my desire to not have to deal with commercial aviation, but also that I enjoy driving more now. I have quiet time where I and my several personalities can discuss things; I have a portable XM radio, I have an MP3 player. It's a lot different now.

I just wonder if the airlines are ever going to 1) acknowledge this and 2) try to do something about it.