I do the whatever is the relevant combination of most valuable and/or pressing at the time, whether work or personal.

If I get work done on the plane, then it's something I don't have to do on the ground. The idea that I work C hours and do whatever I can in those hours and that's how my performance is judged just doesn't apply to my life.

There's always stuff to accomplish, business and personal, and my business life bleeds into my 6am coffee time in the mornings and into my late evenings but I don't have any compunction about talking to my wife during the business day or picking up out of town visitors at the airport when they arrive during the day.

What is this bright-line distinction between personal time and work time of which you speak? This will be controverial, and I don't mean to be normative about it, but I tend to think of that as a concept more appropriate to an industrial era, when we were working at work, maybe in a factory or with machinery.

But those of us who won't, whose roles are strategic, or advisory, or sales, or financial... we do the things that are most valuable at any given moment, maximizing net present value for ourselves through a calculation that includes effort in our jobs and our families and our bobbies. Much more of a unified whole than a bifurcated work/home life distinction.