How could the puppy die in a overhead bin????
Bulldogs like other flat nosed breeds have breathing trouble to start with. I believe airliner cabins aren’t pressurized to one full bar but are at the equivalent of a few thousand feet altitude. The bins aren’t sealed but aren’t ventilated either, they are tightly closed. Most of the volume is filled with bags. The puppy probably slowly ran the oxygen down to a level that didn’t support life. It only takes a drop of a few percent to start hypoxia.
>>How could the puppy die in a overhead bin????<<
Lack of oxygen.