This weekend marks 15 years since the terrorist attacks of September 11, 2001. Each year since, StoryCorps has commemorated the day by featuring stories from the parents, wives, husbands, coworkers, and friends of those who died on 9/11. This year we hear from Vaughn Allex, a man whose life was affected in another way.

Vaughn was working at the American Airlines ticket counter at Dulles International Airport outside of Washington, D.C., on the morning of September 11 checking in passengers on Flight 77. Allex1As he was wrapping up, two men who were running late for the flight came to his counter.

Before the creation of the Transportation Security Administration (TSA), airport security was more lax, and Vaughn did exactly what he was supposed to do — he checked both men’s IDs, asked them a few standard security questions, and then flagged their bags for extra scrutiny.

Vaughn then checked the two men in and they boarded the flight to Los Angeles.

Those two men were among the five hijackers onboard who crashed American Airlines Flight 77 into the Pentagon, killing 189 people including themselves.

Vaughn, who retired from the airline industry in 2008 and now works for the Department of Homeland Security, came to StoryCorps with his wife, Denise, to discuss how he has felt since learning the next day that he checked in two of the 9/11 hijackers on American Airlines Flight 77.

Originally aired September 9, 2016, on NPR’s Morning Edition.

Illustration by Matt Huynh for StoryCorps.