What is the thickness of this bag? Is it sturdy enough to be checked as luggage on a plane? I will not be using it for artwork, but need something large to put an item 22 in x 26 in and about 3 inches thick. I would put cardboard on each side for some protection.
In my opinion the bag is definitely sturdy enough for your purpose, and will expand width-wise to accommodate your package. The bag is soft sided and will not stand on its own so make sure your item is strong enough to withstand the baggage handling rigors of air travel.