The Patagonia MLC is a must for the constant traveller. The MLC stands for Maximum Legal Carry-On, and it was designed for just that. It will fit everything you need to take with you on your trips without having to check luggage. It is meant for the traveler and has multiple pockets with external pockets for your passports and tickets. It doesn’t have the security features as the Pacsafe or Travelon, nor does it have a TSA compliant laptop space like the Timbuk2. But what it lacks in features it makes up in space. This is the biggest messenger bag you can take on carry on with you and thus makes this the best messenger bag for travel if you don’t want to check your luggage.