looking at the dimensions, its probably going to be a bit too long(tall) to fit under seats in most planes. Probably best to go with something smaller. I've used the Patagonia Half-Mass on many flights and it will fit under the seat, but it's a messenger style bag.

It'll work fine under an ariline seat - I've got the Chacabuco pack which is a tad bigger and travel with it all the time and always have it under the seat in front of me.

It'll work fine under an airline seat - I've got the Chacabuco pack which is a tad bigger and travel with it all the time and always have it under the seat in front of me.

provided it's not packed super full of stuff, it'll fit fine