"AIRLINES ARE UNSAFE FOR PETS" (msu.edu)

"
The results can be tragic: Five hours after 81 healthy
puppies were put aboard a TWA passenger jet en route
from Kansas City to St. Louis, baggage handlers
discovered 50 of the puppies were dead due to heat
exposure of suffocation. When a Continental jet bound
for Denver was delayed for three hours in Philadelphia,
three of the five Samoyed dogs being transported in the
plane's cargo hold were found dead on arrival. Too
many animals needlessly suffer injury or die each year --
and an airline's only liability for the often gruesome
death of a beloved pet is limited to the value of a piece
of luggage...."

https://www.msu.edu/~silvar/airplane.htm