Originally Posted by
InkUnderNails
If the 12" side is mashable to 10, you are good.
Seriously, a soft backpack will not be a problem. I have seen some monster bags get squeezed into the bins. My Pelican 1510 case is 22 X 14 X 9 and looks huge rolling it around because it has zero flexibility and almost square corners. It is often the smallest bag in the section when the overhead is full.
The backpack is really soft. And it won't be stuffed full. So I would imagine that it would be fine. Do you think that I should be able to stuff it under my seat? Or is it overhead bin only?