Here's a secret that good managers know (and mediocre managers may never understand). Increased productivity does not mean increased time. In fact, the reverse is true. Productivity is defined by work over time. To be more productive, you do more work in the same amount (or a smaller amount!) of time.
Here's another secret: productivity is measured by output — the amount of work you do. It doesn't matter where the work is done. If you can be productive working flexible hours or telecommuting, then productivity is served. Productivity isn't measured by "butts in chairs" over hours at the office.
Productive individual contributors learned the secret years ago. Slowly, over time, good managers are picking it up. More business consultants are speaking and writing about how to enhance productivity and lower stress by decreasing hours "at work" and increasing time with self and family.
June 2 is the (un)official Leave the Office Earlier day, but you can take a stand for productivity — get your work done and go home — any day of any month... starting today.