I'm sure you are aware that all airlines around the world have culled their capacity in view of the pandemic. They have very little revenue and for most of the staff there is nothing to do. There's also little money to pay them. I don't know how heavy the route Edmonton to Phoenix is, but it doesn't feel like much of a trunk route to me, which means that it is to be expected these days that you are rebooked or re-routed. I suspect you are in the tiny minority of people who travel with several pets in the cabin so I don't see this as being some major factor the WestJet's decision-making. I'm wondering why a plane change is such a big deal. Surely it would give the animals an opportunity to be let out of their bags and have a pee or a drink or something.