Fellow passenger Roger Phelps snapped a picture of the woman leaving the flight with the large pig over her shoulder.
Speaking to CNN, Mr Phelps said: "She was talking to it like a person, saying it was being a jerk. I have no problems with babies, but this pig was letting out a howl."
He added: "I understand dogs and cats on planes. They come in crates, but this was way too big, and it had no container.
"It looked heavy. It was not a tiny, cute little pig."
Back in 2003, the Department of Transportation updated its policy regarding animals in air transportation to say that "animals that assist persons with disabilities by providing emotional support" qualify as service animals.
It's then up to the flight crew to determine whether an animal is a service animal.
Weird things you can take on a plane
Weird things you can take on a plane
Fancy spending the duration of your flight knitting? They might look like the type of thing airport security would confiscate but knitting needles are permitted on board. You'll want to leave the your cutting tools at home though, unless your scissors are blunt with blades no longer than 6cm.
Carrying your beautiful wedding cake on a flight isn't the best way to preserve it for your big day but you are allowed to travel with it as your carry-on - as long as it fits in the overhead locker! Heathrow Airport says: "You can take most solid foods, including wedding cake, in your hand baggage if you wish. Foods in sauces or dishes containing a lot of liquid will have to be in containers of 100ml or less, and placed inside a single transparent, resealable plastic bag of a capacity no greater than 1 litre."
This might be surpring for non-hunters but in America, the Transportation Security Administration (TSA) allows travellers to carry antlers through aiport security and almost all US airlines allow them on board. Most will charge a small fee and ask that the anterles are cleaned and for the skull to be wrapped.
Whether you're a smoker or planning on lighting a few candles on your romantic break, you can carry one lighter on board. The UK government website says: "You should put it inside a resealable plastic bag (like the ones used for liquids), which you must keep on you throughout the flight." You can’t put it in your hold luggage or put it in your hand luggage after screening.
Travelling with Etihad Airways? Then your falcon can perch on your lap, too. While the Middle Eastern airline is happy to accommodate flyers who have one pet falcon, you will have to buy a first class ticket if you have two of the birds. Etihad says: "We accept the carriage of falcons in the main aircraft cabin provided that all the necessary documents have been obtained. We also accept falcons as checked baggage."
While some airports will allow Christmas crackers though security as long as they are in their original packaging but you will want to check with your airline if you can carry them on board, too. easyJet allows up to two boxes providing they are seals but warns passengers to check which novelty items they contain as "some crackers contain novelty items – such as sharp objects – that are not permitted onboard as cabin baggage".
Ashes carried in urns can go in your cabin baggage providing the urn is made of wood, cardboard or plastic, as it may not be possible for metal urns to be x-ray screened.
Some airlines will allow you to carry your bowling equipment in lieu of a piece of carry-on baggage. Virgin Atlantic says: "You’re welcome to bring your lucky bowling ball and shoes with you next time you fly Virgin Atlantic. As long as your bowling case doesn’t exceed 23kg, we’ll fly it at no extra charge – in addition to your free baggage allowance." US Airways allows its passengers to carry up to three bowling balls, one bowling bag and bowling shoes.
Spending Christmas abroad? Some airlines will make special accommodations for travellers taking their tree. Your fellow passengers might not be impressed with you dragging an evergreen through the airport. Flybe says: "There are no restrictions placed on passengers by Flybe as an airline with regards to the carriage of plants or trees. If you wish to carry a small plant, this can be carried in the cabin; alternatively this can be placed in the hold and must be properly packed."
If you're a nervous flyer, you might find comfort in carrying your own parachute on your next flight. Passengers travelling with Ryanair are told: "Parachutes of any type, recreational or sports type or paragliding wings (also known as 'canopy') can be accepted for carriage as checked-in or carry-on baggage subject to the standard restrictions for size and weight. These packs may contain an auxiliary or emergency 'chute' and a barometric mechanical activating (auto-release) device. These accessories are acceptable for check-in."
Miniature horses, along with pot-bellied pigs and monkeys, are allowed on flights if they offer passengers "emotional support". A manual from America's Department of Transportation describes them as "commonly used service animals", but that US airlines "are not required to carry certain unusual service animals in the aircraft cabin such as ferrets, rodents, spiders, snakes and other reptiles".
Don't panic if you spot mysterious vapours appearing from a fellow passenger's hand luggage. Some airlines will allow you to carry dry ice to preserve food or medicine. easyJet says: "You can carry a maximum of 2.5kgs of dry ice in your cabin bag as long as it is only used to preserve perishable items that are not classed as dangerous goods."