Aircraft crashes after crocodile on board escapes and sparks panic - Telegraph
We I suppose have to consider uninvited creatures? We all have picked up a wasp or fly who has buzzed around the cockpit enroute to wherever.
Spiders, snakes and even the above link which caused a crash.
No mention of fish? Can you carry the pet shark
I am sure flying the owner of a private jet also involves (subject to boundary crossing regs ) The family Poodle! or the owners Pet Bunny
Pace