For business (and pleasure) I tend to travel. A LOT. A quick solution for weight training - Instead of carrying around your dumbbells carry around two water bottles instead. A 20oz weighs 2.5 pounds. Bring them empty on the plane and fill them when you get to your destination. Fit in any workout!
You can use water bottles in place of dumbbells for almost ANY workout. Even a ten minute basics routine can do wonders. And it helps keep me motivated about my diet!