The 6 best carry-on travel backpacks we tested for headache-free flights

Editor's note: The Outbreaker has since been phased out, but Tortuga's new-and-improved Travel Backpack Pro is a worthy upgrade with near-identical features.

With a highly adjustable harness system, multiple utilitarian organizer pockets, and a four-to-five-day packing capacity, the Tortuga Outbreaker is the only bag you'll need when you travel.

Pros: Incredible organizer pockets, meets carry-on requirements, fits four-to-five days' worth of gear, padded and fleece-lined tech pocket, adjustable harness system, wide hip belt, two water bottle pockets

Cons: Harness system does not stow

The Tortuga Outbreaker is absolutely loaded with compartments, pockets, and hidden gems. Basically, you can put a lot of stuff in a lot of places, and that's why we love it. The front-loader bag opens to reveal a main compartment that fits four to five days of clothes and two large mesh compartments that I used to pack small items like socks and underwear.

Inside the front panel is a deep organizer pocket with wallet-like divisions for cards and pens, and a compartment perfect for travel documents. On the exterior you'll find a water bottle pocket on each side of the pack — a rarity for travel backpacks.

The tech pocket is one of the most impressive at utilizing space. It zips open and lays flat for easy screening, and features two well-padded fleece-lined pockets for tablets or laptops, along with space for storing all your chargers and accessories.

The suspension system is also highly adjustable. You can move the entire thing, shoulder straps and all, up or down the pack to get the perfect fit for a variety of torso heights. The hip belt is one of the widest I tested and it does a fantastic job of redistributing weight off your shoulders — though, admittedly, it's a little dorky looking. Load lifters on the shoulder straps ensure the bag won't sag off your shoulders, creating pressure points.

One downside to this pack is that the harness system isn't stowable, so you may find things get caught as you try to shove it in the overhead. 

Business Insider newsletter editor Jordan Parker Erb uses this internet-famous travel backpack for weekend trips. At less than $40 on Amazon, she calls it "the perfect carry-on bag."

Pros: Affordable, handy shoe compartment, fits under airplane seats

Cons: Too small for international trips, narrow water bottle pocket

The Osprey Fairview/Farpoint is available in two fits with two torso sizes each. All include a wide hip belt and contoured back panel, making for an incredibly comfortable carry and a great choice for every body type.

Pros: Available in multiple styles for a great fit; wide hip belt, load lifters, and a contoured frame sheet make it very comfortable to carry; compressor straps hide external zippers; entire harness system hides away; carry-on compliant on most airlines; lifetime repair/replace warranty

Cons: Not the most fashionable pack, tech pocket at the front is a bit unusual

Osprey offers two different fits in its Fairview/Farpoint line: it considers the Fairview to be the women's fit and the Farpoint to be the men's fit, but each pack can be worn regardless of gender and may better be assessed based on your body type. Within each fit, there are also two different sizes — measure your torso from the base of your neck to the top of your hips to determine what size will suit you best. 

The frame sheet in the back panel is also contoured to help the back hug your lower back and shift the weight of the load away from your shoulders. The hip belt is also wider than the other packs I tested which also makes a difference in redistributing weight.

The harness system is also ergonomically designed and it's one of the few packs on our list with load lifters to keep the pack from sagging away from your shoulders. The entire harness system stows away thanks to a hidden flap that rolls up and zips over the entire thing.

The pack itself is a front-loader with one large main packing compartment with internal compressor straps. A combination tech and organizer pocket sits in front of that. It's the only pack we tried where the tech pocket is in the front, which provides less security, but the external compressor straps affix in such a way that completely hides the zippers so no one can get to them without some serious effort. 

The Incase EO is everything you'll need for short trips. Its main compartment expands to fit up to three days' worth of clothes, and it can easily transition into a day pack to wear while out and about.

Pros: Expands to fit more clothes and contracts to be used as a day pack, lay-flat fleece-lined laptop pocket, organizer pocket has depth for additional storage, carry-on friendly

Cons: Only fits one to three days' worth of stuff, organizer pouches don't zip closed, no hip belt, feels heavy to carry

The Incase EO is the smallest bag on our list by volume, maxing out at 25 liters, but it fits much more than it lets on. It's definitely an overnighter — maybe a weekender if you push it — but it's a well organized little pack that's easily a one-bag solution for light packers and quick trips. It's also unique among our selections in that it's compressible and can transform into a day pack.

The main compartment opens front-loader-style, and while it'll fit a couple outfits, you'll also want to use the space in the organizer pocket to stash some additional clothes. The pouches within the organizer pocket are open at the top, so anything you put in them will simply drop in. I do wish they had zipper closures for added security.

The tech pocket comprises the entire back panel and fully unzips to lie flat for TSA. The laptop pocket is lined with microfleece for extra protection and fits up to a 16-inch laptop. Opposite that is a pouch to slide chargers and other accessories into, though I wish it had a zipper closure and some more pockets to better utilize that space.

Because this pack is smaller, it doesn't come with a hip belt or any way to attach one, and ends up feeling pretty heavy when packed to capacity. But the shoulder straps are well-padded with air mesh, and the sternum strap has some flex to it so it doesn't cut into you while you walk.

Three spacious compartments in the Cotopaxi Allpa allow you to pack more than any 35L backpack we tried, and it still manages to stay a streamlined carry. But it does lack in organizational and tech pockets.

Pros: Easily fits five-plus days' worth of gear, has room for both a 15-inch laptop and a tablet, intuitive compartment placement, meets most airline carry-on requirements, comes with a rain cover

Cons: Lacks meaningful organizer pockets, no space for travel documents, tech pocket lacks space for accessories, shoulder straps are not very adjustable, hip belt may hit too high for those with longer torsos

The Cotopaxi Allpa structures 35 liters in such a way that lets you pack a ridiculous amount of stuff. I fit my entire five-day packing list including sneakers, a sweatshirt, and all my outfits. I didn't have to compromise or pack "creatively" or stick socks into pockets where socks didn't belong.

The clamshell design allows the pack to open like a book. On the right, you'll find an undivided expansive compartment. On the left, you'll find two smaller mesh pockets on the top half and a big compartment on the bottom. There's also a third compartment of the same size that can be accessed externally at the top of the pack.

Accessed by a zipper on the side of the back panel, the tech pocket has a velcro tablet pocket and enough room for a 15-inch laptop, but it lacks accessory pockets. Directly opposite that zipper is a quick-access zipper that lets you reach into the main compartment without unzipping the whole thing. 

The harness system is basic, but the contoured shoulder straps are comfortable, and the removable hip belt is streamlined and effectively distributed load weight. The sternum strap is vertically adjustable so you can get the right fit. And the entire thing is stowable within the back panel. The pack also meets all but the strictest airline carry-on requirements.

With one large main compartment, the Timbuk2 Impulse Travel Backpack Duffel lets you pack a ton of stuff however you see fit, and it throws in some small side pockets and a shoe pocket to further up its utility.

Pros: Large capacity with duffle-style design, both internal and external compression straps, carry-on friendly on many airlines, fits 17-inch laptop, rip-stop fabric

Cons: Tech pocket doesn't open flat, overstuffing could lead to lack of carry-on compliance, shoulder straps may be uncomfortable for those with narrow shoulders, lack of organizer pockets, sticky zippers

The Timbuk2 Impulse is the largest backpack on our list by volume at 45 liters, and thanks to its duffle-style design, you really get to utilize all that packing space. Rather than being broken up into smaller compartments, a U-shaped zipper flap reveals one large one that you can pack however you like. 

It also offers a few friendly details that set it apart from your typical duffle. On either side of the pack — or the top and bottom if you're wearing it — are separate zippered compartments. On the bottom, you'll find a water-resistant compartment for shoes or laundry, and on top is a similarly-sized more flexible compartment.

The tech pocket leaves something to be desired. It's accessed by a zipper on the side of the back panel, and though it's spacious enough to fit up to a 17-inch laptop, there are no pockets for accessories, and it doesn't open to lay flat. There's a distinct lack of organizational pockets on this pack and nowhere intuitive to store travel documents, but that's what you get with a duffle-style bag.

I found the shoulder straps to be a bit wide for my narrow shoulders, but someone broader than me shouldn't have an issue. The sternum strap is vertically adjustable and the hip belt helps disperse the load weight quite well. It felt lighter than some of the smaller-capacity bags I tested, even when fully packed. The entire harness system can be stowed in the back panel of the pack. 

Tortuga Setout ($119): The Tortuga Setout is the little sibling of our top pick, the Tortuga Outbreaker. Despite also being a 35L pack, I was able to fit about a day's less gear than the Outbreaker. The Setout's tech pocket is less impressive and it has fewer organizational pockets than the Outbreaker. Its suspension system is also less adjustable, so you make have to live with a slightly less comfortable fit. The distinct advantage, though, is that it's cheaper. You'll make some compromises to save a few bucks, but they're minor compromises at best. This is still a wonderful pack.

Patagonia Black Hole Duffel ($129): Patagonia's reputation speaks for itself, and this duffel backpack is built to last. Insider's VP of Commerce, Breton Fischetti, has had his for over a decade, and it's still in perfect condition. But the lack of tech pocket, the barebones suspension system, and the fact that it doesn't meet airline carry-on requirements were all strikes against it.

Unlike the Jansport you wore in middle school, travel backpacks have a lot of component parts, many of which are designed to make the backpack more comfortable to carry and less strenuous to your back. But if you don't know the vocabulary, you may have a tough time understanding what you're buying. Here are a few must-know vocab words to give you a better understanding of backpack anatomy.

L: Backpack capacity is often expressed in liters, so if you see a backpack advertised as 35L, that means its total capacity is approximately 35 liters in volume. While the liter measurement can give you a general idea of how much stuff your backpack will hold, the way your pack's pockets and compartments are structured ultimately play a huge role in how much you'll be able to fit. We tested 35L backpacks that maxed out at three days' worth of stuff and some that could easily hold five or more days' worth.

Clamshell: A clamshell backpack features a zipper on three sides with the fourth side acting as a hinge. Clamshell packs open flat like a suitcase and have two equal compartments.

Front-loading: A front-loading backpack opens similarly to a clamshell pack, but instead of the zipper being located in the middle to create two equal compartments, it's located at the front to create one large packing space.

Rear-loading: A rear-loading backpack is exactly the same as a front-loading backpack, except the zipper is located at the back panel instead of the front panel.

Top-loading: Your middle school Jansport was a top-loading backpack. Instead of opening fully flat, you load your items in from the top. We've found that top-loaders provide a worse experience on a large scale than clamshells or front/back-loaders, so we've chosen not to include them in this guide.

Shoulder straps: These are simply the straps that go over your shoulders with which you carry your backpack. They are, in essence, what make a backpack a backpack.

Hip belt: Positioned at the bottom of the pack, a hip belt wraps around your waist, just above your hips. A properly positioned hip belt helps shift the weight away from your shoulders making larger loads easier to carry.

Sternum strap: A sternum strap crosses your chest and connects one shoulder strap to the other. It should sit just below your collarbone, and like the hip belt, it aids in weight distribution.

Frame sheet: A frame sheet is sewn into the back panel of a backpack and helps the backpack maintain its shape once fully loaded. It may be contoured or padded for extra comfort and can also help with weight distribution.

Load lifters: Load lifter straps help pull the top of your backpack closer to your shoulders. Not every pack has them, but if yours does, you'll find them coming over the top of the shoulder straps. Packs without them tend to fall away from your shoulders which adds strain.

Suspension/harness system: Every entry above from shoulder straps to load lifters is part of your backpack's suspension or harness system. It's everything that contributes to how you carry your backpack and how the load's weight is distributed across your body.

Compression straps: Compression straps can be located externally to help cinch down a packed backpack to make it smaller, or internally to help keep clothes in place if you haven't packed your backpack to capacity.