When the animals are shown running past Bugs Bunny's mailbox, there are large trees in the background.
A later scene shows the mailbox again but there are no trees at all in the background.
After the just married Tasmanian Devils get on the plane, you see a man roll away the steps to the plane and the plane immediately takes off, but the man and the steps disappear.
When the Devils are exchanging their vows, their voices swap.