The hamster likely wouldn’t travel in any different environment than any other animal who travels in cargo, and they survive just fine.
I think many carrier planes have 2 types of cargo bins...pressurized and unpressurized. Caged pets are put in the pressurized bins...well, most of the time. You’ll read about it on the Interwebz if Fido is put in the UNpressurized bin because he’ll arrive at his destination cold and lifeless.