When my daughter and son-in-law were moving to CA. ,last summer, Jet Blue refused to fly their Golden due to the July heat. They opted to drive for 5 days and the happiest one on the trip was the dog. Her favorite place is in the car so she was in heaven. It actually turned out to be a great trip, their youngest drove with them while her brothers flew.
My Great Dane absolutely loves the back seat of my SUV. Of course, that leaves the question of where to put the people . . .
I thought most airlines had a heat rule, usually 85 Fahrenheit. If it’s warmer than that at any destination, the pets can’t fly.