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Seek Outside Flight One Backpack Review

Seek Outside Flight One Backpack Review

The Seek Outside Flight One Backpack is a lightweight 61 liter internal frame backpack that weighs 2 pounds 4 ounces. With a max recommended load between 35 – 50 lbs (depending on torso length and frame height), it’s built to withstand hard use for wilderness backpacking and thru-hiking. The Flight has a lightweight aluminum frame, an adjustable-length hip belt, and all of its exterior pockets are made with solid fabric to avoid the ripped mesh that plagues so many lightweight backpacks. The pack is available with two different fabric options: SpectraGridHT (which we explain below) or a combination of SpectraGridHT and XPac, that make the Flight highly abrasion-resistant and virtually waterproof.  The Flight One is the first internal frame pack produced by Seek Outside, which is primarily known for their lightweight external frame backpacks. That expertise is clearly manifest in this awesome new backpack.

Seek Outside has a new version of this backpack called the Flight Two.

Specs at a Glance

  • Weight: 2 lbs 4 0z
  • Volume: 61L (3700 ci)
  • Gender: Unisex
  • Frame: Internal
  • Closure: Roll Top
  • Pockets: 6, including hip belt pockets
  • Hydration compatible: Center hose port
  • Load lifters: Yes
  • Bear Canister Compatibility: Yes, depending on the model, canisters can be stored vertically or horizontally inside the pack, or secured to the top with a Y-strap.
  • Materials: Solid SpectraGridHT – tested (also available in XPac with SpectraGridHT pockets)
  • Torso Range:  15″-21″ (see below)
  • Hip Belt Sizing: 26″-38″, 36″-48″
  • Max recommended load: 35-50 lbs, depending on frame height and torso length

Seek Outside Flight One Backpack


Bomber Tough but Lightweight

The Seek Outside Flight One Backpack is ideal for what I would term wilderness backpacking where you are hiking on-trail or off, without frequent resupplies, and you need to carry heavy or bulky loads like extra water, packrafting equipment, and bear canisters. The Flight would be equally at home on any triple crown trail particularly if you have or want to do heavy water carries, carry bulky equipment, luxury items, or extra food.

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Backpack Storage and Organization

The Flight One a 61L rolltop backpack with two side water bottle pockets, each capable of carrying 2 x one liter bottles and a large front stretch pocket that’s good for storing extra layers or wet gear. All of these pockets have elastic at the top to keep their contents from jumping out and drain ports at the bottom. The water bottle pockets are 12″ deep, but reachable while wearing the backpack if you use a tall soda or Smartware bottle.

The Flight One is a rolltop pack with side water bottle pockets and a large front stretch pocket
The Flight One is a rolltop pack with side water bottle pockets and a large front stretch pocket

The pack’s hip belt has two large pockets with waterproof zippers. Seek Outside doesn’t count the side pockets or hip belt pockets in their volume calculations, so the pack feels like a *big* 61 liters in volume. The hip belt pockets are really oversized and dwarf my largish Smartphone. Each one is 8″ x 5″ x 3″ (close to 2L each.) I fill mine up with navigation equipment, my Smartphone, sun gloves, a head net, Tenkara fly fishing tackle, chlorine dioxide tablets, a CoVid mask, and anything else I need to access during the day so I can retrieve it without having to stop and take off my pack.

The main compartment is cavernous but lacks any internal organization. There are two hang loops on the inside that you can hang a water reservoir from, with a central hose port between the shoulder straps. There’s also a frame sleeve to hold the aluminum frame, but you’re probably not going to ever want to remove the frame because it makes the pack what it is. That frame sleeve has a cavity/opening that you could use as a pocket for smaller items, but it’s not really large enough to hold a higher capacity hydration bladder.

You can carry a large bear canister (Garcia) in the extension collar and still close the roll top. How cool is that?
You can carry a large bear canister (Garcia) in the extension collar and still close the roll-top. How cool is that?

Bear canisters do fit inside the Flight, which is a huge plus for a pack that weighs so little. For example, my black Garcia canister fits horizontally in the extension collar with plenty of slack left over to roll the rolltop closed. It doesn’t fit vertically though due to the shape of the frame, which has a significant arch. Both the Bearvault BV450 and the BV500 fit vertically, according to Seek Outside.  There’s also a top Y-strap that can be used to lash a canister to the top of the pack, which is pretty standard on roll-top packs

While the main compartment closes with a roll-top, the ends of the roll-top only clip to each other, not to buckles on the pack body. While one of the benefits of a roll-top pack is expediency, a second is top compression, which is lacking on the Flight because the roll-top doesn’t clip to the pack bag. While there is a top Y strap that runs over the roll-top, I found that the roll-top would unfurl when the pack was not completely filled to the gills. It’s not a showstopper, but I wish there was some way to secure the ends of the roll-top to the sides or front pack bag with gatekeeper clips instead. It’s just not possible given the pack’s current buckle setup. Short of that, adding a stiffener or snaps to the top of the extension collar would help prevent the top from unraveling. As it is, you just need to check it a few times a day when you stop to take a break.

The side water bottle pockets are reachable if you use tall soda or Smartwater bottles
The side water bottle pockets are reachable if you use tall soda or Smartwater bottles

The exterior of the pack has three tiers of fabric loops along the side and rear seams so you can run up to three tiers of side compression straps along the sides, or around the back (which is handy in winter for carrying snowshoes). The Flight comes with extra compression webbing straps for this purpose. The compression straps have gatekeeper buckles at the ends so you can move them from one set of loops to another. If you squeeze these buckles the little metal gate pops open so you can detach them and move them from loop to loop. For compression or gear attachment, I prefer webbing straps over the use of cord, which is common on many UL packs. I think it’s much easier to use and provides much more compression.  A lot of brands use these buckles now, but Seek Outside was one of the first to introduce them several years ago on their Gila 3500 Backpack (see review).

Gatekeeper compression strap buckles
Gatekeeper compression strap buckles

Backpack Frame and Suspension

The Flight One is a fixed-length internal frame backpack with an aluminum perimeter loop. It’s not a U-shaped stay, but a 360-degree loop, not unlike those used on Seek Outsides external frame backpacks. Mid-way down the back, there’s also a horizontal stay, called an intrusion bar, that stiffens the frame and creates a cavity behind your back. Depending on your fit, that cavity can provide a ventilation benefit to keep your shirt drier in warm or humid weather. Seek Outside could have covered it with mesh, but adding cute features to their packs isn’t in their DNA.

The Flight One has an aluminum perimeter frame
The Flight One has an aluminum perimeter frame

The Flight Shoulder Straps are sewn to the back and come with load lifters. The straps are backed with soft spacer mesh and J-shaped. Unfortunately, the front of the straps do not have sewn-on daisy chains to attach accessory pockets or navigation equipment to, although I bet you could ask Seek Outside to sew some on for you. There are however plastic buckles sewn near the top of the strap that you can hang a small biner from (for an inReach, for example).

The shoulder straps are very comfortable but only have plastic buckles for hanging gear or pockets from.
The shoulder straps are very comfortable but only have plastic buckles for hanging gear or pockets from.

The Flight Hipbelt has a center buckle with a top and bottom adjustment strap on either side so you can make the top tighter or the bottom half of the hip belt depending on the shape of your hips and preference. The hipbelt is removable and attached to the pack with velcro behind a very soft and unobtrusive lumbar pad.

The Hipbelt has a center buckle with top and bottom adjustment
The Hipbelt has a center buckle with top and bottom adjustment

The two halves of the hip belt are themselves attached with velcro and so you can adjust the hipbelt length. The hipbelt is surprisingly soft and supple and lined on the inside with spacer mesh. Its 4″ width is beefy but not as wide as the hipbelts found on Seek Outside’s other external frame and hunting backpack backpacks. The hip belt wraps my hips well and I haven’t noticed any slippage, even when carrying loads north of 45 lbs.

The hipbelt length can be adjust by up to 10” by repositioning where the two halves join.
The hipbelt length can be adjusted by up to 10” by repositioning where the two halves join.

Torso Size x Frame Length x Max Recommended Load

The Flight One is available in two different frame lengths: 22″ and 24″ that have different load-carrying characteristics depending on your torso length. This isn’t something you’ll find on other internal frame packs which take a one size fits all approach to maximum recommended loads regardless of frame height and torso length. Whether that actually reflects reality is another matter. This chart copied from the Seek Outside website summarizes the relationship. My torso length is 19″ and I tested the 24″ frame because I like to option to go heavy on certain trips.

Torso LengthFrame - 22"Frame 24"
15"50 lbs-
16"50 lbs-
17"50 lbs-
18"45 lbs50 lbs
19"40 lbs50 lbs
20"35 lbs45 lbs
21"+30 lbs40 lbs

The nice thing about having a 2 lb 4 oz backpack with a max recommended load of 50 lbs is that you can do heavy water carries with it. To test this out, I loaded up the pack with my regular backpacking load, food, fuel, and fishing gear, plus 10 liters of water to see how the pack would carry with 45 lbs in it. I was very surprised that the hip belt didn’t slip or buckle under the load since it doesn’t have any stiffeners sewn into it. I’ve had to carry loads like this in the past on long unsupported trips and really suffered because my pack’s frame and hipbelt did buckle under the weight. But the Flight One handled it with surprising ease and I’m pretty sure I could have carried even more, up to its 50 lb weight rating or even beyond it.

SpectraGridHT Fabric

The Flight On is available in solid SpectraGridHT or a combination of XPac and SpectraGridHT. What is SpectraGridHT? It’s 100 denier high tenacity nylon with a PU coating that has a 200 denier Spectra fiber reinforcement with a very tight grid pattern, creating a highly water-resistant fabric. Spectra is in the same class of Ultra High Molecular Weight Polyethylene (UHMWPE) fibers as Dyneema and highly abrasion-resistant. Because the Spectra fibers are bigger than the Nylon in SpectraGridHT, they take the brunt of abrasion, performing similar to 500 denier Cordura.

The ability to reroute the compression straps provides a lot of flexibility for carrying different types of loads.
The ability to reroute the compression straps provides a lot of flexibility for carrying different types of loads.

Seek Outside’s SpectraGridHT also has a hydrostatic head of 1500 mm, which is much more than other backpack fabrics with the exception of Dyneema DCF and XPac. If the Flight One were a tent it would be considered waterproof, except for the fact that Flight One’s seams are not seam-sealed. While you’ll still want to line the pack with a pack liner, the Flight isn’t going to absorb much water when it rains, so you don’t need a pack cover too. If you’re trying to decide between the all-SpectraGridHT pack versus the pack made with a combination of XPac and SpectraGridHT (on the exterior high-abrasion surfaces), the SpectraGridHT is recommended for drier and rockier locations.

Comparable Lightweight Backpacks

Make / ModelVolumeMax LoadWeightPrice
Seek Outside Flight One (XPac)61L35-50 lbs34 oz$299
Seek Outside Flight One (SpectraGridHT)61L35-50 lbs34 oz$319
ULA Circuit XPac68L35 Lbs39-47 oz$320
Elemental Horizons Kalais XT52L45 lbs42.8 oz$360
Gossamer Gear Mariposa 6060L30-35 lbs31.2 oz$260
Hyperlite Mountain Gear 3400 Southwest56L40 lbs35 oz$345
Osprey Exos 5858L40 lbs42.4 oz$220
Osprey Levity 6060L25 lbs31.2 oz$270
Superior Wilderness Designs Rugged Long Haul 5060L40 lbs31 oz$269


The Seek Outside Flight One is a 61L lightweight backpack that weighs 2 lbs and 4 oz but can haul loads between 35-50 lbs, depending on the frame length you purchase and your torso length. It’s ideal for what I would term wilderness backpacking where you are hiking on-trail or off, without frequent resupplies, and you need to carry heavy or bulky loads like extra water, packrafting equipment, and bear canisters. The Flight would be equally at home on any triple crown trail particularly if you have or want to do heavy water carries, carry bulky equipment, luxury items, or extra food. In terms of comfort, I can’t think of any backpack I’ve reviewed in the past few years that comes close to the Flight One, particularly in terms of hip belt fit and ventilation. I love the flexibility of the external attachment system, the fact that the pack has functioning load lifters, large hip belt pockets, and the durability and waterproofness of the SpectraGridHT fabric.

The only tweaks I’d recommend making to the pack would be to add daisy chains to the upper half of the shoulder straps and adding a stiffener or snaps or even velcro to the roll-top to keep it reliably closed when the pack is not “bursting at the seams”. Those are minor changes you could probably ask Seek Outside to make for you, but they don’t significantly detract from the awesomeness of the Seek Outside Flight One Backpack. Highly recommended!

Disclosure: Seek Outside donated a backpack for this unbiased review.

See our other Seek Outside Backpack Reviews

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  1. Thanks for the review!

    SO offer extra straps for 6 bucks that can be used to attach the roll top to the sides of the pack:

  2. Awesome review, Philip! I’ve been looking forward to this one. It’s great to hear you can reach tall water bottles from the side pockets while the pack is on–I had wondered about that with the height of the pockets.
    With SO’s focus on user repairability, I am curious about the decision to sew in the elastic to the pockets, when their larger packs have easily-accessible and replaceable shock cord.
    Regarding the roll-top, it looks like Seek Outside has a strap and buckle kit here for 6 bucks: that allows you to clip the roll top buckles to the sides and have top compression.
    “In terms of comfort, I can’t think of any backpack I’ve reviewed in the past few years that comes close to the Flight One…” –that’s a pretty stellar recommendation! Good stuff.

  3. For top compression, you can attach a strap with a gatekeeper on one end to one of the lower tiered fabric loops along the frame. At the other end of the strap put the mate to the pack bag closure. My Gila came with these straps included.

  4. Great and informative review as always! Now for the $300 question: how do you compare this pack to the HMG Southwest 3400? If you had to pick one? These are the two I’m deciding between and I haven’t found any side by side comparisons. With REI’s Labor Day sale coming up to help with the price of a Southwest, let’s say the prices are equal. I would love to hear your thoughts.

    • I was just thinking about that myself as I was hiking out of the woods after a backpacking trip. Would I rather carry the Flight than the 3400 SW across Scotland? I think I’d go with the Flight for a few reasons. Bigger and much easier to use front stretch pocket, much much better hip belt pockets, Much more space in the extension collar for a 7 day food carry. Load lifters. The 3400 isn’t a bad pack, but the fixings are really not that great. I’d still find a way to add daisy chains to the Flight shoulder straps though.

      • Thanks for that insight. Have you had any issue with “head clearance” – your 19 inch torso vs 24 inch frame causing you to bump your head on the pack when looking up or ascending steep terrain? Also, since you mentioned Scotland, you feel that the Flight is as waterproof (or water resistant) as the HMG, or nearly so? Thanks again!

        • No issues with head clearance. I use a plastic bag liner in both backpacks (I’ve also worn a hole in the bottom my HMG). Rain doesn’t normally phase me much because I put my valuables in dry sacks. The Flight is nowhere near as waterproof as the Southwest, but over 1500mm, it really doesn’t matter that much.

      • Can you share how big (more specifically “long”) the front stretch pocket is? Like for storing a TT Notch. Also, do you think the XPac version would be an improvement to the stiffness of the collar fabric? Thanks!

  5. Compared to the Gila?

    • The Gila is an adjustable length external frame backpack capable of carrying a 150 pound load even if you’re not. Very different kind of pack compared to an internal frame, fixed length pack like the Flight. Not sure a blow by blow comparison even makes sense.

  6. Thanks, Philip! Just what I was looking for.. ordered one (via link from your article). Appreciate it

  7. Can you comment/compare against the Kalais in terms of carrying comfort at 45 lbs?

    • They’re very comparable. It’d be hard to choose between them on that criteria alone. Consider that the Kalais is an adjustable torso pack and the Flight isn’t. The Kalais also feels narrower.

      • Great review as always! The Kalais (& XT) & the Flight are top of my list too. I can’t go anywhere without a bear can around here which begs the question (since you graciously pointed out the Flight can handle one horizontal… what about the Kalais in regards to a bear canister? Thanks Philip!

      • If you can afford a Bearikade you would be able to custom fit the bear barrel to your pack dimensions …..

  8. I have a Granite Gear Crown VC 60, which has been a fairly nice pack but I’m not so impressed with it that I wouldn’t consider something else.

    The Flight One weighs about the same as the Crown and seems from your review to carry a load extremely well. I like the tougher and more secure exterior pocket setup on the Flight since I don’t store drinks in the side pockets. With my back problems, I’ve never been able to return a drink bottle to the side pocket on any pack. Hence, I hang drink bottles from the shoulder straps, which works well for me.

    Another pack I’ve been intrigued with is the Zpacks Arc Haul series along with an additional side pocket. This pack would weigh about a pound less than either of the above, which is a major consideration, and I do like the trampoline frame. One reason I like that frame is that it would help keep the pack away from my shirt. The Flight frame would do the same. The Crown sits right on my back, which gets extremely sweaty–of course, backpacking is a sweaty endeavor in any case. The Zpack model and the Flight are in the same general price range. I like the large size of the hip belt pockets on Zpacks and the Flight. The GG belt pockets are quite a bit smaller.

    My winter load for a 2-3 day Texas mountain hike (with water haul) and autumn load for a week on the AT is about 32# (I’ll eat those weights down about 1.5# per day).

    From my perspective, the Zpack and Flight probably compare more closely to each other and the Crown is a different beast altogether. I know I’m trying to compare apples to oranges to grapes but do you have any ideas on how these will compare to each other? I’m not opposed to adding to my exorbitantly large supply of packs but I’d like to get one I’ll be inclined to stick with.

  9. Hi Philip, many thanks for the review! I am thinking of ordering a flight one myself

    I have one question regarding the hipbelt.

    How do it feel? Does the hipbelt velcro attachment system feel secure? Does it collapse a bit under heavier loads?

  10. I wonder it the SO Flight One is as comfortable as theOsprey EXOS 58? I’ve never had a pack more comfortable, even my pricey old Dana Terraplane.

  11. Philip- I read your reviews with interest. I have tried several different backpacks for long distance hikes and have yet to find one with a short enough hip belt. I am looking for a hip belt with a range of 22- 26″ and torso length of 15-16″ and about 55-65L volume

  12. I just ordered one using your link. I called SO first to clarify a few things. They were responsive and helpful. Will let you know how it works. I use an HMG, but it has a few issues I’m hoping this pack will resolve.

  13. Any chance a Stratospire Li could fit inside, up high, horizontally? And is your Garcia bear canister smaller than the BV500? I thought they were similar & was hoping I could fit my BV500 inside horizontally as well. Great review! You really hit the points that matter. Thanks Philip!

  14. Question to Douglas A Stephens’ reply regarding Bearikade: I own a BV500, & yes it’s a pain – like most if not all hardsides. The Bearikade carbon fiber is indeed expensive – but I would consider it if the total kit solution is superior – given most of my hiking is Pisgah & the Smokies. Could you elaborate? Why could I custom fit the Bearikade (Weekender?) to my pack & not the BearVault500? And how? I see I’d save maybe 10 oz too. But I’m not clear on the custom fit options Bearikade offers & BV doesn’t. Really appreciate the insight! Thanks!

  15. Never mind Douglas A Stephens – I now see that Bearikade makes custom cans too. Thanks for the heads up. However, a) I could buy a backpack for the cost of that can & b) if I did think a truly bespoke pack/can solution was worth it – I wouldn’t relish determining the size I want particularly without the backpack. …Wonder if Matthew over a Elemental Designs has collaborated with the guys over at Wild Ideas. Probably not a bad joint venture move. Thanks!

  16. Curious how this pack compares to the Flex Capacitor, which is also designed to carry ~50 lbs comfortably. Any thoughts how the Flight One compares to the Capacitor in that regard? Also wondering your thoughts on the back and hip belt comfort between these two packs (especially considering the stiff back panel on the Capacitor, as noted in your review). Thanks!

  17. It would likely be a Notch Li so I think I’d have to roll it. That won’t work?

  18. Philip,

    Could you elaborate a little on bear can options with this pack? First, in addition to being able to fit one (the Garcia anyway) in the extension collar, what are the real limitations for vertical inside given the intrusion bar (say for a BV500 or 450)? They say on their site they can fit inside/horizontal but above the bar (I think). If you packed your sleep system in the bottom & the can on top of that – how would that work? And 2) Do/did you find it a comfortable carry in the extension collar? That’s weight fairly high up. I’m wrestling between this pack & just getting a HMG 3400 from REI & trying it out for a while (since you can return it if it doesn’t work out).


  19. Hi Philip,
    It seems from one of your answers to a previous question that you think the Xpac VX21 fabric that Seek Outside uses is more durable than the SpectraGridHT. Did I understand that correctly? I’m considering a Seek Outside pack for off-trail hiking and was wondering whether to choose the Xpac or the SpectraGridHT fabric.

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