I think most people would be best served packing light, and using a carry on size “travel pack” which is a cross between a backpack and soft-side luggage. Travel packs will often have light weight internal frames to make them easier to carry, handles on the top and side to carry as luggage, and backpack straps and maybe a waist strap that tuck away in case you need to check the bag through. If you have no plans to check your bag, a classic daypack can function beautifully as a “travel” pack.
Most travel packs are really designed for urban use with an emphasis on ease of use rather than multi-hour carry comfort. Travel packs address keeping the contents organized, easily accessible, and have clean lines so they don’t get hung up on things. I find most travel packs can be carry <10 lbs for an extended timeand between 10-20 lbs for an hour or so. If you are planning to be walking long distances with your pack, you would be better served by using either a trekking pack if your days end in a town, or a wilderness backpack.
Luggage which is 7.8×12.5×18 inches is carry-on legal on all airlines, and will generally fit under the seat in most commercial jets and in all the overhead bins. Most airlines permit the bag to extend a bit beyond the seat, so 7.8x13x21 will typically be acceptable for carry-on and will typically fit under the seat. Many airlines specify overhead bags as being less than 45 linear inches. There are a few things you need to watch out for. It’s possible to overstuff soft side bags to the point that they will not fit, even it the bag is theoretically the “permitted” dimensions. Electronics and infrastructures is intruding into the under seat luggage space on some planes. Finally, some regional / ultra budget airlines tickets only permits a “personal” sized item which is smaller than a full carryon bag. For example, RyanAir limit the size of your small ”personal bag” to 40x25x20cm (15.7x10x7.8in) which must weight less than 10kg. I have found the RyanAir size personal bag has fit under the seat in front of me on every flight I have been on but there are airlines which are even more restrictive. There is a summary of common carry one restrictions, and a exhaustive periodical table of carry on size limitation. When it doubt, check with your carrier.
Make sure the travel pack you are considering is still under the limit for carry-ons! Feature and size creep has resulting in many travel packs which are heavy and are too big to be used for carry-on. At the same time the airlines have been reducing the size/weight limits of carry on bags.
I use daypack rather than classic travel packs. When I don’t to need too many “options” from my packing list I use the packable version of the Gossamer Gear Vagabond Jet. When I need to bring more in an urban locations , I use a Tom Bihn Synik-30 Backpack. It’s large enough for every every trip I have taken, while small enough that it has never been viewed as “luggage” which needed to be checked-through or stored in the under-carriage. I have found this pack (and the very similar Synapse packs) are beautifully designed with just the right amount of organizational features that allow me to find my daily use items without wasting space or having too many compartments. On trips that mix my travel with wilderness backpacking I use a Gossamer Gear Gorilla backpack which is carry-on legal provided I don’t over stuff it.
Travel packs vary in the amount of “organizational features” they have. One approach is to divide the bag into sections which often directly accessible from the outside of the bag. In theory is it’s quick and easy to retrieve a particular item without disturbed most of the pack’s contents. If the way you separate you items matches the size of these compartments this works quite well. The other extreme is that the bag is just one large space (with maybe a pocket or two for small items). This has the advantage of being very flexible. The downside is that finding things in the one large section can be challenging. People typically manage this by using packing cubes or stuff sacks to collect smaller items together. In between are bags that have external access to compartments, but the divider is light and flexible materials that allows the main compartment to “take back” space not used by the small compartments. I personally tend toward the one big compartment, though my Synik30 has numerous compartments.
Below are a list of travel packs which I think are worth a closer look. This is list is in roughly in my preferred order.
- Gossamer Gear Vagabond Jet: super minimalist 23L pack with few organizational features, light weight, durable, and carries well. If you are traveling ultra-light could be a nice option. I am using the even lighter, but discontinued packable version.
- Osprey Farpoint 40: Less functional volume than some of the maxi-volume carry-on size bags which is offset by a real frame that is comfort carrying 15-25lb (similar to the frame on the first generation Osprey Aether backcountry pack), external water bottle pockets, a large pocket on the opening panel, a padded slot for laptop, a number of built in straps to keep everything in place. If the load is less than 10lbs, I would prefer several of the following packs over the Farpoint, but as the weight claims the carry comfort of the Farpoint is quite good.
- ULA Camino: A full feature back country backpack which has been designed to be travel friendly. It’s heavier than what I need, but if you are going back and forth between city and back country with a heavy load and need a carry-on sized bag, this is your pack.
- Bags from Tom Bihn: All the bags made by Tom Bihn are amazingly well thought out, have great organizational features, and are top quality. Choose the bag that fits your packing need and style, but be prepared to pay for the quality. The downside of Tom Bihn bags is that they don’t have the class leading weight to carry volume nor are they the most comfortable when carrying significant weight for longer durations. If you are carrying a heavy weight, you will likely prefer one of the other travel packs listed that have padded waist straps. We will see if this continues with Tom retiring and the company purchased by a capital management firm.
- Tortugaback Packs is a small company that makes packs specifically designed for the light weight traveler. Suitcase like zipper opening, side access laptop sleeve, zip away straps, and other features make this a well designed travel pack. Waist belt actually transfers weight.
- Cotopaxi Allpa 35l was a Indiegogo funded project but now easily purchased at stores like REI. Well designed bag that unzips suitcase/clamshell style with zippered mesh compartments. Has a fair number of organizational features and externally accessible laptop compartment. Hip belt does a reasonable job of transferring weight. Wish it had an external pocket to carrying water. This bag calls attention to itself with the bright, multi-color fabrics pieces.
- REI 40L Rucksack is a pack which can transfer some weight to the hips, is easy to purchase, and reasonably priced. It can stretch to be used in the back country if you are carrying an ultralight load.
- Peak Designs Travel Backpack 45L is a kickstarter project from a company that has delivered numerous successful projects designed for photographers. This bag would be ideal for photographers, and would be a good bag for just about anyone. The back has good access and organizational features, and opens likes a suitcase. The hip belt actually takes some weight off the shoulder making it comfortable carrying moderate loads. It can be slimmed down to 35L by closing two side zippers and snaps (which have a tendency to pop open when pressured). It’s very durable, though a bit heavier that I would like.
- Opsrey Porter 46: A durable bag which will protect the contents better than many other bags because there is closed cell foam sewn into the sides which also gives some structure without adding much weight. The “strait-jacket” compression system is very effective but the straps need to be released when you want access to the main body of the pack. There a fairly large top pocket which I put everything I might want quick access to while on the move. The lid to the main compartment has an external accessible zippered pocket, and a mesh pocket on the inside. One side of the bag has an internal mesh pocket which runs the length of the bag. This is one of the more comfortable carrying bags I have found though the hip strap is more stability than weight transfer. This pack unfortunately doesn’t have an external water bottle and is a light on organizational features. This was my primary bag for ten years. There is also a 30L version of this pack. Note: Osprey periodically makes minor updates to this bag, at which point you can often find “last year’s model” on sale for less than $100.
- Rick Stevens Back Door Bag: A great value. Typically less than $80. Light weight. All the features that are critical. Not as refined as the bags listed above, but also significantly cheaper.
- Minaal Carry-on is a pricey bag that was a successful kickstarter project. The bag zips open like a classic suitcase for easy access, has an external water bottle pocket, removable straps, and a well designed padded pocket for a laptop. Clear design, but the webbing waist strap is only for stabilization, not load transfer.
- Nomatic Travel Bag is a kickstarter project bag designed for travel. Well designed with a lot of organizing features. Clamshell opening, shoe compartment, side storage pockets, internal waterproof water bottle pocket. I don’t have personal experience using this bag but it seems well regarded.
- MEI: One of (if not the first) travel pack makers. Very durable, carries well. Hard to find in local stores… when doing mail order you might need to wait for your bag to be built.
- Patagonia Cragsmith 45l: No personal experience but saw one recently, looked good, and the owner loved it.
- Patagonia MLC: Nothing special but nothing particularly wrong either. Basic travel bag with backpack style straps that hide away.
- Marmot Long Haul, Northface Basecamp Duffel (Small), etc: Very durable and highly water resistant. A good option if you expect your bags to be outdoors a lot and you aren’t looking for organizing features (Marmot has a few features, TNF none). I didn’t find either as comfortable to carry as the Osprey Porter, but would choice it if I expected my bag to spend a lot of time exposed to the elements. Many other outdoor companies make similar duffels with straps which are roughly equivalent: Patagonia, REI, etc. Consider how easily the straps come on and off, and what against your back.
- Decathlon Forclaz Travel 100, 40L Hiking Backpack: Inexpensive travel backpack. No experience but worth a look.
- eBags Luxon bag is reasonable design. It’s often on sale for around $100.
- ULA Atlas: A 40L Travel Pack designed by people who normally do back country backpacks. I have not seen it in person, but likely has a better suspension than most of the other travel packs and lighter weight. Won’t have all the organizational features of some of the fancier travel packs, but for many people that shouldn’t be a problem. Carry-on approved for many airlines, but several limit you to 22″ and the Atlas is 23″.
- Rangeland New Business Trip Backpack: $45, qualifies as a personal item with most airlines. No personal experience but several people recommended it.
There are a number of other packs which I don’t have experience with that might be work looking at such as GoRuck, AER, Standard Luggage Traveler. There is a spreadsheet of popular onebags and an analysis of what bags are being used by the /r/onebag community.
Packs for Trekking or “Wilderness” Backpacking
Remember that you can’t take fuel on a plane… plan to acquire at your destination. You can’t bring knife, stakes, or hiking poles as carry-on. If you need to carry these things, you can ship them via a postal carrier, send them through as checked baggage (cardboard poster containers work well), or send your backpack as checked luggage. If you are shipping your backpack as luggage I encourage enclosing it in either a duffel bag or cardboard box. Other hints about flying to reach backpacking destinations.