How 9/11 Changed Air Travel and Airport Security 25 Years Later

For millions of Americans who travel by air each year, the security process at airports has become a familiar part of the journey. But much of today's system did not exist before September 11, 2001.

The terrorist attacks 25 years ago transformed commercial aviation security, bringing new screening procedures, federal oversight and security responsibilities for passengers and airline employees.

Two months after the attacks, Congress created the Transportation Security Administration, or TSA. The agency has since grown to more than 60,000 employees and operates under standardized security procedures at hundreds of airports across the country.

Aviation security consultant Jeff Price says the difference between flying before and after 9/11 is difficult to overstate.

“I think the first thing is anybody born post 9/11 would not recognize pre-9/11 security.”

Among the major changes were mandatory security screening for passengers and checked luggage, expanded use of identification requirements and the continued use of federal terrorism watch lists.

The Federal Air Marshal Service also expanded significantly. Before 9/11, the program had only a few hundred officers. Today, several thousand federal air marshals work to protect the nation's aviation system.

Cockpit security also changed dramatically. Commercial aircraft were equipped with reinforced cockpit doors designed to resist forced entry and withstand ballistic and explosive threats.

The role of flight attendants evolved as well. Crews have increasingly received training to respond to unruly or violent passengers, a concern that became particularly visible during the COVID-19 pandemic.

Passengers themselves are now considered another layer of aviation security.

Former FAA and NTSB investigator Jeff Guzzetti says travelers have become more alert to unusual behavior aboard aircraft.

“Passengers are now very wary of other passengers that may be acting erratically,” Guzzetti said. “I think, in general, the flying public is readily more able to react more quickly.”

There has not been another successful hijacking of a commercial aircraft in the United States since the September 11 attacks. But attempted attacks, including the 2001 shoe bombing attempt and the 2009 underwear bombing attempt, have continued to influence aviation security.

After 25 years without another hijacking in the United States, aviation security experts say complacency remains a concern.

Price says the absence of another major attack should not lead travelers or the aviation industry to assume the threat has disappeared.

“Complacency is probably our most dangerous opponent right now,” Price said. “Simply because nothing has happened in 25 years doesn't mean something couldn't happen in the next 25 years.”

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