[LydiaLong]

Must have been cold.

[proudpapa]

He’s lucky it wasn’t a longer flight.

[Ciaphas Cain]

There have been cases of trans-PACIFIC stowaways riding in unpressurized baggage compartments. But they had to figure out how to sneak aboard a LOT of insulation, thick blankets etc. Otherwise one is almost certain to freeze to death.

It's extremely risky. Few survive. But it can be done.

[Vigilanteman]

Actually, cargo holds must be kept above freezing due to possible liquid components in the cargo, including checked passenger baggage. They must crank it up even higher if pets are on the cargo manifest.