If you thought Samuel L. Jackson was sick of snakes on a plane, let's hope he doesn't get on a flight where someone brings a pet kangaroo on board.

More and more people are flying with their pets -- in the main cabin.

It's not just dogs and cats. Social media is full of pictures of kangaroos, pot-bellied pigs and even a rooster in a tutu, on planes.

All you have to do is get a doctor's note saying you need your animal for emotional support. How hard is it to get your pet classified as an Emotional Support Animal? Courtney Copenhagen, a producer at NBC station WMAQ in Chicago, decided to test it out. The answer: not hard. She went online, answered a few questions, paid $150 and a few days later received the letter in the mail.Then she flew round-trip from Chicago to Minneapolis with her 70-pound Labrador retriever, Bailey and a borrowed, 15-pound sulcata tortoise named Xena.

This may all seem pretty cute and harmless, which it is, if like Courtney, your animals are well-behaved. But Copenhagen discovered that there have been hundreds of complaints about service animals and dozens of incidents where flights had to return to the gate because of unruly or disruptive pets.

So you might want to order your pet a relaxing drink in the frequent flier's lounge before takeoff.