Your best course of action is to bring them as extra size cabin luggage. Anything short of that would be rolling the dice, and the best outcome would still be

Your best course of action is to bring them as extra size cabin luggage. Anything short of that would be rolling the dice, and the best outcome would still be a horrible experience for the pet. Edit: even on companies with “pet friendly” adjustments. Looking at how they treat special luggage and other “no really, I’ll pay for it so treat it nice” cargo, I wouldn’t trust major airline companies to be consistently good with animals.