Terrorists are the No. 1 enemy of TSA agents, but cats are a close second. They scratch, hiss, hate being picked up, and don’t respond to commands. Believe it or not, cats need to get patted down, too (lest we have another feisty feline commandeering a plane), and sometimes they use this opportunity to make a break for it. If they get through security prior to a proper search, the animal is deemed a security threat, and an entire terminal could be potentially shut down in response.