There aren't many guarantees in life but airline passengers misbehaving from time to time is certainly one of them. 2019 saw plenty of poor choices, from intoxicated travelers acting out mid-flight to drug and animal smugglers. Arrests were made and flights were delayed. As we head into 2020, it's time to look back on the worst of the worst this past year.

In March, a flight was forced to return to Saudi Arabia's King Abdul Aziz International Airport after a mother realized she forgot her baby in the boarding area. The bizarre incident went viral with social media users praising the pilot for his poise and requesting permission from air traffic controllers to return to the airport after the woman eventually notified the cabin crew.

A woman's profane tirade at Florida's Fort Lauderdale-Hollywood International Airport went viral in early January after she was seen screaming at a JetBlue employee, calling him a "rapist" and claiming to have a gun on her while hoisting herself onto the counter several times. The woman was apparently upset that she was denied boarding because she was suspected of being intoxicated.

Two men were busted at Nashville International Airport in January when security officials caught them with approximately 159 pounds of marijuana packed in four oversized checked bags. Authorities estimated that the confiscated weed had a street value of more than $50,000. Meanwhile, four men were arrested at Hartsfield-Jackson Atlanta International Airport ahead of the Super Bowl in February after getting caught with an incredible 224 pounds of marijuana.

A teenage boy was arrested in Alaska in February after he allegedly took control of a small plane during a short commercial flight. The 16-year-old was accused of grabbing the aircraft controls shortly after takeoff, pulling them back to force the plane upward and then pushing them forward to send the aircraft into a dive.

Chinese carrier Lucky Air sued a passenger after he allegedly threw coins into a plane engine for good luck as he was boarding a February flight from east China. The foolish move cost the airline $21,000 and impacted more than 160 passengers.

In March, a drunk passenger allegedly urinated on a woman's luggage during an American Airlines flight from Chicago to Charlotte, North Carolina. The flight was met by law enforcement and the FBI was notified. Meanwhile, a woman was banned from flying TAP Air Portugal after a meltdown stemming from a lack of Pepsi on a 90-minute flight from Portugal to Spain.

A man was detained at Chicago's O'Hare International Airport in March after being caught on camera walking around on the tarmac completely naked. The nude traveler was reportedly attempting to board a departing flight.

A woman caused quite a stir in November when she faked a medical condition to get a bigger seat on an American Airlines flight from Pensacola to Miami. The hoax backfired when the pilot declared an emergency and returned to the airport, leading her to fess up to the lie.

A man was arrested at an airport in Delhi, India after posing as a pilot while attempting to board an AirAsia flight earlier this year. The man had a fake Lufthansa pilot ID that he used to gain access and privileges at airports.

A Colombian man was caught attempting to smuggle 35 pounds of liquid cocaine inside of shampoo bottles at Houston's George Bush Intercontinental Airport in November. The illicit liquid narcotic filled as many as 24 full-sized shampoo bottles and was valued at over $400,000.

Sixty-seven-year-old, Marilyn Hartman, also known as the "Serial Stowaway" for her repeated efforts to sneak onto flights, was once again arrested after attempting to pass through airport security with neither her ID nor a boarding pass. The latest incident occurred at Chicago's O'Hare International Airport, where she is prohibited from entering without a ticket.

In October, a climate change protester disrupted a flight at London City Airport after he climbed on top of a British Airways plane. James Brown, who is also a Paralympic bronze medalist, livestreamed the incident before he was arrested.

A woman was arrested in September after she opened an emergency exit door because the cabin felt "too stuffy." The Xiamen Airlines flight was delayed for more than an hour as a result.

A man prompted an American Airlines flight to make an emergency landing in Denver back in September after informing fellow passengers that he was on cocaine, locking himself in the bathroom and even lighting up a marijuana cigarette in the cabin. The man was removed from the plane and the flight continued on to its final destination.

In August, a Polish man was found with dozens of tarantulas smuggled in his luggage at an airport in French Guiana. The man, who was arrested, told authorities that he's "passionate about insects."

An American woman was detained at Ninoy Aquino International Airport in Manila, Philippines this past summer after she was caught with a six-day-old child in her carry-on bag. The woman claimed to be the baby's aunt but only had a passport for herself.

A Malaysian man was arrested by Houston police in August after allegedly planting a hidden camera in an airplane bathroom aboard a United Airlines from San Diego to Houston several months earlier. The device was discovered by a first-class passenger who noticed a blue blinking light.

A teenager found himself in hot water over the summer after sending threatening messages about blowing up a plane at Houston's George Bush Intercontinental Airport on Snapchat. The posts were shared with the FBI and the 17-year-old Texas native was charged with making a terroristic threat.