The sticking point of packing for a trip: You know you’ll need another purse or backpack once you get there, but you don’t want to pay to take an extra bag on the plane. We have the answer! It’s a full-size backpack that stows easily into its own zip pocket. And it weighs practically nothing. So you can toss it into your suitcase or carry-on – and have just the bag you need once you reach your destination.