Osprey Sojourn Porter 46L Travel Backpack

I picked this one because a 46L carry-on that opens like a suitcase is exactly the format I look for when a trip needs to stay to one bag. The StraightJacket compression and tuckaway harness are the details that matter to me, since they keep the load compact and let it carry comfortably through airports. Before you buy, check your airline's carry-on size limits and make sure the packed dimensions work for how you travel, since a full 46L can get heavy fast.