I'm thinking the total number is around six:

Some kitty math: How many lives did little tabby Gracie Mae use up when she crawled into her owner's suitcase, went through an airport X-ray machine, got loaded onto a plane, thrown onto a baggage belt and mistakenly picked up by a stranger far from home?

And doesn't that give you a great "warm n' fuzzy" about the effectiveness of TSA luggage screeners? "Socks... Camera... Cat skeleton... Shaving cream... Underwear..."

Via Yourish.