Another stowaway is caught on a Delta flight this holiday season – raising major concerns about airport safety

Delta Air Lines planes are seen parked at Seattle-Tacoma International Airport on June 19, 2024, in Seattle, Wash. (Kent Nishimura / Getty Images)

Yet another stowaway managed to board a major airline’s plane – renewing serious questions and concerns about airport safety during the busiest travel season of the year.

This time, a stowaway tried to hitch a ride on Delta Air Lines Flight 487 at Seattle-Tacoma International Airport on Christmas Eve.

The unticketed passenger was discovered while the plane was still taxiing out for takeoff to Honolulu, Delta Air Lines told CNN. The Transportation Security Administration and the Port of Seattle confirmed the incident to CNN.

The incident came less than a month after another stowaway boarded a Delta airplane Thanksgiving week. That unticketed passenger made it all the way from New York’s John F. Kennedy International Airport to Paris before she was eventually arrested.

And on Christmas Eve, a body was found in a wheel well of a United Airlines plane shortly after it travelled from Chicago’s O’Hare International Airport and landed in Maui.

Hiding in a plane’s wheel well is the most common method used by stowaways, the Federal Aviation Administration said. Stowaways often get crushed when the landing gear retracts, and oxygen levels plummet as a plane reaches higher altitudes.

In the Seattle incident, the stowaway went through a TSA security checkpoint the evening before the flight but wasn’t holding a boarding pass, an airport spokesperson told CNN.

The next day, the person “gained access to the loading bridge without a scanned ticket at the gate,” airport media relations manager Perry Cooper said.

Once the person was discovered, the Airbus A321neo returned to the gate to remove the unticketed passenger, Delta said.

Port of Seattle police officers were dispatched to gate B1 at the airport around 1:05 p.m. for “a report of a suspicious circumstance” on the Delta flight. The person “ran out” of the aircraft before officers arrived, Cooper told CNN Friday.

“The aircraft returned to the terminal and the subject departed the aircraft,” the Port of Seattle said. “With the help of video surveillance, POSPD were able to locate the subject in a terminal restroom. The subject was arrested for criminal trespass.”

The unticketed passenger didn’t have any prohibited items, the TSA told CNN.

“The aircraft was swept by K9 as well as all areas in the terminal accessed by the subject,” the Port of Seattle said. “The aircraft was deplaned and all passengers were escorted by TSA to return to the security checkpoint for rescreening.”

The Port of Seattle deferred any further questions about the subject to the airline. Delta declined to comment further due to the nature of an ongoing investigation. Delta’s system “is sound,” airline spokesperson Morgan Durrant told CNN, a point the airline has reiterated since the Paris incident last month.

Delta said the flight was delayed by two hours and 15 minutes. After the rescreening, it continued to Honolulu at 3 p.m.

“We were kind of left in the dark,” said Brady Bly, a passenger on the flight. Travellers were eventually told they could not depart due to a security breach, Bly told CNN affiliate KIRO.

“It’s kind of scary if somebody could just sneak on the plane like that,” Bly said. “I don’t think Delta did everything they could to protect people on the flight.”

Delta apologized to passengers and thanked them for their patience in a statement this week.

“As there are no matters more important than safety and security, Delta people followed procedures to have an unticketed passenger removed from the flight and then apprehended,” the Atlanta-based airline said in a statement. “We apologize to our customers for the delay in their travels and thank them for their patience and cooperation.”

TSA said it “takes any incidents that occur at any of our checkpoints nationwide seriously. TSA will independently review the circumstances of this incident at our travel document checker station at Seattle/Tacoma International.”

'Embarrassing' for TSA and Delta

How the person got through airport security is a question many want answered. There are a number of factors at play, according to former commercial airline pilot and aviation analyst, John Nance.

“There are multiple causes that come into this, and they probably involve not only a bit of lackadaisical inattention,” Nance told CNN affiliate KING. “It may be training, it may be compliance, but it’s probably all of that.”

It’s “embarrassing” for this situation to happen twice to the same airline and TSA, according to former Department of Homeland Security official Keith Jeffries, who was federal security director when he left the DHS in 2022.

In his 20 years working with DHS and the TSA, Jeffries said he’s seen these situations multiple times.

“It has happened before. It will happen again until they continue to strengthen that vulnerability,” Jeffries said.

“The fact that it happened to the same airline, of course, couldn’t be more embarrassing, especially back-to-back, and during the holiday season, when there’s an extra alertness associated with the large holiday season,” Jeffries added.

During the holidays, Jeffries explained, there’s typically more staffing at the airports being “extra vigilant.” TSA, airlines and airports have even more people present to ensure things like this don’t fall through the cracks, making these cases “even more concerning,” he said.

If there is a “silver lining,” Jeffries said, it’s that Delta did catch the stowaway during the taxi, and they didn’t make it to Hawaii. The stowaway also didn’t have prohibited items when scanned through TSA, which is another plus, he said.

“Everybody’s going to have to work together; TSA and the airlines on how they can strengthen both of those vulnerabilities, and in some cases, even work with the airport,” he said.

Congress will likely scrutinize these incidents, Nance added. “But there will be no one paying more attention than the airlines themselves,” he said.

CNN’s Holly Yan, Pete Muntean, Amanda Musa and Nicole Chavez contributed to this report.