Here’s what you want to know:
"Does it actually fit under the seat as a personal item? SOMETIMES. It fit under the seat without a water bottle in side pouch on one united flight and with a water bottle on frontier. It was tight both times. You will have very little leg room. It did NOT fit under the seat on my recent United flight to Alaska. It also does NOT fit in the personal item sizer that frontier has outside the gate when fully packed. It does fit in the carry on sizer when fully packed. So proceed with caution on frontier, you can make it work if the gate staff aren’t stingy, or you can take some stuff out and shove it in your pockets or something when getting on the plane. It will fit in the personal item sizer if it is not fully packed. And proceed with caution on any flight really because it might not fit under the seat when fully packed. Is it comfortable? No. I’m a 5’9” girl, not comfortable. My 6’3” male partner wore it on a hike, still not comfortable. Maybe someone would find comfortable, but unfortunately, we didn’t, even if it wasn’t super packed. I wish it had a hip strap. Packing - Overall it’s really great. You can stay really organized and it packs really well. Love the thoughtfulness and design in the pack overall. Looks sleek, got a compliment on it at the airport even. You can fit a lot of stuff in it. It's pretty water resistant which is great. Not waterproof. Took it on a rainy hike in Alaska with my laptop in it (was motorcycle camping, no other choice), and it survived! Overall a great pack, I do recommend it, but be wary of the size, it might not fit under an airplane seat, and it isn't very comfortable to wear unfortunately."