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.