R.I.P. Bandit, the border collie belonging to Funday PawPet Show founder Yappyfox.
UPDATE (8:35 AM): I found a couple of Rubbermaid containers that would fit my car: the Roughneck 66-quart tote (16.5 inches wide) and a large FlexTote (15.7 inches.) The latter has a zipper closure to make it more secure for flying. Both are clear.