eaglecreekswitchback - upright luggage suitcases

I mention it here in case you manage to come across a used one somewhere. A popular choice for touristing and adventure travel was a two-piece modular pack: a main pack of maximum legal carry-on size (21.5 x 14.5 x 9"), plus a zip-on daypack (16 x 12 x 6"); for carry-on, of course, you separate the two components. It weighed 4.25 pounds (1.9 kg), and came in black, blue, and evergreen (pictured here). Its suspension stowage system was particularly convenient and flexible. The advantages of this and similar bags are — obviously — more space, and a very convenient daypack; disadvantages include increased weight (some of which will be due to the increased space!), and the fact that collectively the two pieces exceed carry-on size. This is fine in North America, where two carry-ons are generally allowed; it''s also acceptable for train travel, the most popular form of European transportation. For most other airline travel, though, you''ll likely end up having to check one of the pieces. A further drawback is that the addition of the (zipped-on) daypack moves the bag''s centre of gravity further from your body, making it less comfortable to carry for longer periods of time. Finally, note that there is no reason why you can''t unzip the daypack and carry it inside the main pack, resulting in an overall package of legal carry-on dimensions.