Originally Posted by
jimrpa
Couldn't the horse travel in the cabin as an "emotional support animal"?
Sorry, I couldn't resist

Truth, it is stranger than fiction:
I was on a DC-9 DCA-DTW that had to offload pax after the pilot requested extra fuel because of bad weather. I don't think there's any great mystery here after you look at the flightaware map, and consider altitude/TO temps.