Meeting most airlines' carry-on requirements, the Topo Designs Global Travel 30L Bag features plenty of internal and external pockets to keep us organized in the air, on the road, and on the tracks. The 30-liter capacity can expand to 35 liters, leaving plenty of room for our travel cubes, folded clothes, and outdoor gear. We also like the Global Travel bag's multiple carrying options—backpack straps, shoulder strap and grab handles—to lug our clothes and gear around in several ways.