"animal hold"

But the biggest coincidence was their dogs being on the same US flight.
Jenny said: “All four of them were in the same animal hold. "It is like we have been nearly meeting so many times that it makes sense we are twins – like we were meant to be together.”
More: Twins find each other 55 years later...

Does hold in here mean "The lower interior part of an airplane where cargo is stored?"

Nearly. That's the cargo hold. The animal hold is a separate section.

Rover