I have one you could borrow, that should hold two cats providing they're not a couple of fatties
The cage/basket was used to transport my cat from USA to UK in July and is very robust.
The measurements are 21" high 18" wide and 26" long.
If that's not big enough, I also have a huge one that brought the dog over.
Send me a PM if you're interested and I'll try to take some photos to send.