Does commercial bread use baking powder? My understanding of baking powder is that it supposed to be a chemical alternative to yeast, allowing a baker to leaven bread more cheaply and faster than yeast would do.

Is baking powder the primary method for leavening commercial breads that I would find in a grocery store like "Wonder Bread" and "Sunshine" and so on?
No way. I have 3 loaves of (different brands) commercial bread open at home now. None of them lists baking soda, baking powder, sodium bicarbonate or any other synonym I know of, and all three do list "yeast". In addition, Amazon website gives the ingredient list for the authentic "Wonder Bread classic white bread loaf", and it also calls out yeast, and not baking powder.