Little funny story from my side about a passenger with two cats on a Swissair-flight about 15 years ago:

In Economy, a woman had 2 cats with her in a kennel. After the meal, she asked the MC if she could have the cats on her lap, as they were sedated anyway. He gave permission but told her, that she has to make sure they will not roam around, cause it's impossible to find a lost cat again in a Boeing 747 during a nightflight.
Well, the lady fell asleep and when she woke up, one cat was missing. Big halo about it, we informed all the FA's in all sections that a cat was missing. It took not long to find it. She was sitting in First Class on Alain Delon's lap enjoying salmon...