Worked perfectly for what I had in mind. The travel from El Paso to Juneau Alaska was made simple with this bag. It carried my T4i w/attached EFS 18-135mm lens/hood, EF 100-400mm L lens w/hood, EF 17-40mm L lens and Speedlite flash. I also carried a 4G LTE MiFi Jetpack and Canon VIXIA HF R40 video camera and extra batteries. Other items included an iPad mini, asst. cables, straps, the bag's rain cover, cleaning supplies a book on photography, headphones and a light rain jacket. I'm not sure if it would easily fit under an airline seat because I never tried. I'm 6'1" and needed the room for my legs. I was fortunate and able to easily store it in the overhead compartment just above me. The bag and straps were comfortable for my frame and I walked the trails around the Mendenhall Glacier, Mt. Roberts trail to Gastineau Peak and other areas around the lakes, islands and the north coastal road. I took it with me to shoot humpback whales and finally my son's wedding in Glacier Gardens that included a ride up to the peak that overlooked Juneau Airport and the coastal inlet into Juneau. This bag will definitely be with me on future trips.

Though I'm rating this four stars, I decided not to keep the bag. It's very compact and with my three prime lenses and 70-200 zoom plus Canon Mark 3 camera body, there was still room to spare. The weight felt well distributed across my back, and I really liked that there are handles on the top and side for easy grabbing. My issue is that the configuration of the compartments doesn't easily house a camera body that is attached to a lens any bigger than a pancake, so this was useless for my purposes - I need a bag I can carry on and then lug around in the field for wildlife photography, where the shots can strike at any moment -- one needs to have the camera set up with the lens on it, ready to go at any moment. There are probably awkward workarounds for this that weren't apparent to me at the time. I also decided not to keep the bag because there isn't really any room to carry a small cosmetic pouch for all the essentials you would need while on the plane (unless that pouch is tiny, and extremely flat). Ideally a bag of this complexity would have a bit more give for items like that, but it is very rigid and compact.

This backpack is a worthwhile investment, especially for the photographer that loves to travel. Last trip I took, I wanted to pack "light" (I only do carry-ons when I travel.) As it turned out, I didn't need to leave anything at my home/studio that I wanted to bring. It's honestly wild how much gear this bag can fit. And the inserts are nice and rigid, so your valuable equipment stays well put. Think Tank must have an airplane seat in their test facility that they used to gauge the size of this thing, because it fits under the seat like a glove! (literally not an inch to spare.) I know the price might seem steep if you've never bought something like this before, but I can speak from experience that I've had cheaper backpacks before, and you get what you pay for. In the grand scheme of things, you'll likely be putting thousands of dollars worth of gear in here, so what's a couple hundred bucks to protect it, right? Trust me, it's worth it. This is a great quality product.

This is a wonderful backpack. First off, yes, I have flown with it and had no issues on small regional flights. Fully loaded, this thing is extremely comfortable. I am a portrait and wedding photographer and on local jobs, prefer to ride my bike just for convenience. 4-5 mile rides with this are no problem. I have also taken it on 6-8 mile hikes with again, no issues. The build quality is fantastic with strong stitching and thick material that feels sturdy, but doesn't add a lot of weight. The dividers are very stiff and overall, the inside of the pack protects gear very well. As a semiprofessional working paid jobs, I also like the slickness of the design. It looks professional. While the quality of my images is the ultimate sign of my abilities, clients confidence is important as well. I'd rather have them think I'm going to provide high quality images and then follow up on that. Here is a list of what I can pack into mine. Typically I won't carry all of this, but the space is there.
Bodies:
Nikon D7100
Nikon D5000
Pentax 35mm film body

Lenses:
Samyang 85mm 1.4 (attached to the D7100)
Sigma 17-50mm 2.8
Nikon 55-200 4-5.6
Nikon 50mm 1.8
Nikon 35mm 1.8 (with macro tubes attached)
Pentax 50mm 2 (attached to the Pentax)
Tokina 28-70 3.5-4.5

Other:
12.5 inch laptop and mouse (sometimes with the charger)
Two spare batteries for the digital bodies
2-3 spare rolls of 35mm film
Full sized flash and wireless triggers
4 spare AAs for the flash
Small 8 inch soft box
3 77mm filters for the sigma
Portable battery pack and charger for the D7100
Small first aid kit
Bottle of advil (for longer weddings)
Spare caps, tools, contracts, business cards, pen, etc."¦

On the outside:
33-inch umbrella
65-inch tripod
Water bottle

Point is, this bag can fit a ton of gear and STILL fit in the overhead. Combine that with the cable lock, and you've got a winning combination.

I was looking for a backpack that could accommodate a DSLR, a couple of lenses (including a long zoom), a video cam and associated gear (batteries, chargers, etc.). After some research, I found the Think Tank backpacks are highly recommended. I ordered this one for several reasons:

1. Very lightweight.
2. Fits under the seat on most aircraft
3. Has room for my gear
4. Allows attaching a tripod or monopod on one side
5. Can carry a small laptop AND a tablet
6. Has waist and sternum belts
7. Has a top AND side handle for carrying

I recently "test drove" the bag on a short trip and am very pleased. All my gear fit securely--camera, 2 lenses, video cam, batteries, monopod swivel head, chargers, laptop, Kindle, binoculars, papers, a magazine. The laptop and tablet are a somewhat snug fit--it helps to fully unzip the top section into which they fit (which also covers the camera section) and then slide these items into the designated pockets. I opted to carry the monopod in my other carry on so as not to tempt TSA to see the monopod as a "weapon" ;-). If one double loops the pod-carrying straps, they are snug enough to easily hold a monopod.

The pack has smaller compartments in the top section but don't plan on storing other than fairly flat items in the two zippered compartments on the camera side--for example, storage cards, lens caps, small cables, etc. Some compartments on the laptop side are closed by velcro but most are open, with places for pens, and perhaps a pad of post-its, small notepad and the like.

The camera storage area comes with several small pads that allow configuring the space for your gear. The pads are secured in place by velcro and it is STRONG--no worries about the pads shifting once you locate them.

The backpack shoulder straps each have a small metal ring to which you could clip small items, and all the straps all have a clever "flap" that serves as a stop after you adjust the length. I also like that the straps can be fairly easily "dressed" out of the way to minimize dragging on the floor and through grunge, or the chance the excess will form an inadvertent snare catching one's foot.

Once I packed the bag, it was rather heavy--it is easy to load it up! I think if I had used the waist belt more it would have been more comfortable on my back.

I left at home the weather cover; as others have noted, it takes up space in the main storage comportment instead of being stuffed into a bottom zippered compartment the way other Think Tank bags handle it. That's about the only "drawback" I can think of to an otherwise excellent backpack to safely and securely carry a reasonable amount of camera gear on a trip. One of my brothers was so impressed he decided to buy one, though I believe he chose a somewhat larger model (he's also much bigger than me!).