I'm taking five flights to and from conferences in the next few days. It will probably be close to 10 hours of time just sitting on the plane. So I'm going to try to do as much work as I can during that time. It's not because I want to be productive all the time. I actually want more time to be unproductive.
It's important to have downtime to do what you want to do, time that's protected from work and other obligations. But there are two kinds of downtime–1) Time when you could work, but could choose not to. 2) Time when you absolutely do not want to work, when you choose to do whatever other things you want to do, without guilt or apology. That's real downtime. If you want more of the second, shift more work to the first.
I don't have to work on the plane. But while there's nothing particularly fun or rewarding I want to be doing during that time, there are a lot of things I want to do on Tuesday when I get home. So I'll protect that real downtime on Tuesday by filling the time on the plane. Using more of the first kind of downtime will create a lot more of the second kind for me when I get home.
The idea isn't to fill every waking second with work. It's to acknowledge that real downtime is sacred. You need it to function well. So protect it from work. When that time is off limits to obligations, you'll feel a greater sense of urgency to focus and get things done when you get down to work. And you'll end up with more downtime because of it.