I have always said I've never had an issue with Spirit however today was the day. I've had a carrier that I have used on Frontier, United, American, Delta and was told today that despite my carrier being fine on every other flight (we're talking 10+ flights), that my carrier was "too tall" so I was charged $45 for a carrier that is longer than my original one and my dog can hardly turn around in. They also made me throw out my original carrier.