Around noon in Seattle on Sept. 11, 2001, in the hours after terrorists struck the World Trade Center in New York, senior manager of airport operations Mark Coates was driving his truck on the runways of Seattle-Tacoma International Airport.

Sea-Tac was like a “ghost town” as flights across the country had been grounded following the attacks, and he was the only person out on the near-silent airfield that typically held thousands of workers.

Then, seemingly out of nowhere, an F-15 fighter jet raced through the sky above him at a low level and flew over the airport, over Seattle, and out of sight. 

“It was the most unreal feeling,” Coates said. “It was part of the security presence, that the government was showing force, that this was serious — and you felt it. You felt it in your veins.”

On the morning of Sept. 11, 2001, two hijacked planes struck the twin towers of the World Trade Center in New York City. A third struck the Pentagon, and a fourth crashed in a field in Shanksville, Pennsylvania. It was the deadliest terrorist attack on United States soil and there were nearly 3,000 casualties among civilians and first responders.

Twenty years later, the impact of the 9/11 attacks is still felt around the world — from the site of the attacks in New York, Virginia and Pennsylvania, to Sea-Tac Airport.


The attacks changed the way the U.S. approached airport security, and marked the birth of the Transportation Security Administration. Seemingly overnight, passengers went from being able to walk through security in minutes to having to show photo ID, remove their shoes and go through a stringent security screening before boarding airplanes.  

“It’s a solemn occasion, it’s one we won’t forget. It changed the industry forever,” Coates said. “9/11 changed the way we did everything.”

LeeAnn Subelbia was working as the food and beverage manager for HMS Host, the airport food service company at Sea-Tac, on 9/11, and said her team had to send all the airport’s nearly 400 concession and restaurant workers home. 

“It was extremely eerie, and you had to wonder, ‘OK, what’s next? Are they going to start attacking other airports?’” Subelbia said. “We were at the highest security alert and there was security everywhere checking everybody’s IDs.”

The day after 9/11, Sea-Tac’s operations dropped to zero — no passenger flights went in or out of the airport. The week after the attacks, passenger volume was just 74% of the previous year’s traffic, and monthly flight traffic did not exceed 2000’s levels until June 2018, said Perry Cooper, media relations manager at Sea-Tac.

While airport security has come a long way, TSA officials at Sea-Tac say there are still active threats to passengers, and the security system is constantly evolving to address those threats.


For instance, in 2020, firearms were confiscated at double the rate — both locally and nationally — they were in 2019. In 2021, 74 firearms have been confiscated from security checkpoints at Sea-Tac so far, according to Lorie Dankers, TSA’s Pacific Regional spokesperson.

“Security changed forever”

Before 9/11, the TSA did not exist. Private security companies appointed by airports or airlines operated the screening process. 

Passengers could bring everything from baseball bats to box cutters on board, and did not have to show photo ID. Loved ones could accompany travelers to their gate and watch them board the plane.

“Security changed forever. Before 9/11, I used to be able to bypass security because everybody knew me,” Coates said. “After 9/11, that was no more. … You started to feel like you were a stranger in your own airport.”

President George Bush signed the Aviation and Transportation Security Act in November 2001, which established the TSA to oversee security screening for passengers and baggage. By 2002, more than 60,000 employees were recruited to the TSA nationwide.

Over the years, the TSA evolved and expanded in response to security threats detected at airports around the world. Rules such as the ones requiring passengers to take off their shoes and limit their liquids were imposed periodically over the past 20 years in response to specific security threats. 


“In December of 2001, there was a shoe bomber who wanted to detonate his shoe on a plane, and here we are 20 years later, still taking off our shoes … because we know that continues to be a threat,” Dankers said.

Later, in August 2006, British police caught terrorists who attempted to detonate liquid explosives carried on board at least 10 airliners traveling from the U.K. to the United States and Canada. 

Susan Hegdahl, a TSA transportation security inspector, said she was called into Sea-Tac in the middle of the night after news of that plot broke. She helped develop a new protocol overnight in response to that threat in which they initially banned all liquids from carry-ons. One month later, the TSA allowed passengers to bring on 3.4 ounces or less of liquids in their carry-on baggage.

“We had trash cans all over the airport,” Hegdahl said. “It was difficult, it was hard, but we got through it.”

Dankers said people were very unhappy about the change, and the lines were very long because of the confusion.

The next big change came in 2017 when the TSA began requiring passengers to remove all electronics larger than a cellphone from their carry-on luggage due to an “increased threat to aviation security.”


Explosive devices can be concealed inside electronics, security officers say. Removing those devices gives officers a clearer view of the item during security checks.

“It is a lot harder to see without the electronics outside of the bag,” said Roxy Northcutt, supervisory transportation security manager.  

Subelbia said the transition from pre-9/11 to post-9/11 security levels was dramatic, and some passengers were frustrated.  

“The security was crazy, and it took a long time, and people had a hard time dealing with it,” Subelbia said.

While these security steps can be cumbersome and cause lines to move slowly, Dankers said they are put in place in direct response to security threats.

“It’s hard to measure success when there have been no major incidents in this country [since 9/11],” Dankers said. “But I can tell you, every single day, our officers are finding prohibited items, we are detecting guns at a record pace, both locally and nationwide, in carry-on luggage to this day.”


In 2020, Dankers said the rate at which passengers brought firearms in carry-on luggage was at its highest since the industry’s inception, despite the record-low travel volume that year. 

In 2020, TSA officers at Sea-Tac discovered 7.4 firearms per million travelers, compared to the 3.6 firearms per million travelers found in 2019.

“We have to be right every single time. We can’t let even a small mistake occur, and if it does, we need to rectify that immediately because that threat is out there,” Dankers said. “We’ll continue to do that long after the 20th anniversary, but this is a great way to stop, pause and remember what occurred, and we have a responsibility moving forward.”

Chris Baden, TSA deputy federal security director for Washington, said the TSA conducts random tests of its systems year-round. The agency will periodically send in officers posing as passengers, both overtly and covertly, with test items to see if they can be detected.

He said the TSA is actively looking for security vulnerabilities and any threats found abroad to inform new technology. 

Advanced imaging screening, which detects hidden explosives on the body and Credential Authentication Technology, which screens for fake identification and members of the terrorist watch list, are among the latest security measures added to airports across the country.


“We’re out there scanning the horizon for things happening worldwide that could impact aviation or transportation security, and that helps to inform where we might be going with respective changes to our technology,” Baden said.

Reflecting on the attacks 20 years later

When the planes struck the twin towers, Northcutt was just 14 years old. Ever since, she said, she knew she wanted to serve her country, and chose to join the TSA when she turned 19.

“It was a huge impact on me,” Northcutt said. 

She said every day when she’s working in security lines, she reminds her officers to “work on the floor as if your family’s on that aircraft.”

Hegdahl was working at the airport for Northwest Airlines on 9/11 and her supervisor encouraged her to join the TSA as it was being established at Sea-Tac. 

“I was deeply affected,” she said. “The airport is like a little city, so when something happens … we’re just kind of like a family.”

Every year on 9/11, a small group of TSA officers, firefighters and police officers gather at Sea-Tac to honor the fallen first responders. 


This past Wednesday, Sea-Tac dedicated a 9/11 memorial created by retired Port of Seattle firefighter Allen Martinez. 

Martinez started to fill the seventh floor of the airport garage’s stairwell in 2014 with pictures of the twin towers getting hit by the planes, as well as the recovery efforts to honor the fallen firefighters, police officers and emergency medical technicians.

During his firefighting career Martinez said that every week, Port of Seattle firefighters read an obituary of one of the fallen before putting on their full set of gear and running up nearly 80 flights of stairs in their honor.

“I want them to remember the 343 firefighters, 70 police officers and eight EMTs that died on 9/11,” Martinez said. “That’s one way we can honor their memory and their sacrifices.”

Subelbia said after the attacks, she remembers the patriotism and hope that spread across the country, and that many people banded together to support first responders and families impacted by the attacks.

“It still makes me really, really sad that that happened,” Subelbia said. “When you live it, it  just stays with you forever.”