When I expect that I have to bring back many belongings from my destination, on my way to the visiting place I put a business bag (black one to the left) into a knapsack (blue one to the right). So, I bring only one bag. Since I do not have to check-in the knapsack to an airplane, I can pass an arriving airport quickly.
If goods are many, as expected, I separate the two bags.
I bought this blue knapsack four years ago when I lived in Thailand. As far as I remember it cost Baht 550 (approximately 1,600 at a rate on a purchased date but approximately Yen 2,050 at a current rate)