On September 11, 2001, the United States changed forever. Terrorist attacks across the country exposed critical vulnerabilities in the nation’s aviation security system and created an urgent need to rethink how the country protected its transportation networks.
In the weeks that followed, the federal government took swift action to strengthen aviation security, leading to the establishment of the Transportation Security Administration (TSA) on November 19, 2001. Since then, TSA has grown and evolved alongside emerging threats, technologies and transportation needs, becoming the agency responsible for protecting the nation’s transportation systems.
As TSA approaches its 25th anniversary, its history provides important context for why today’s security processes exist, how they have changed the passenger experience and how the agency continues to protect the transportation systems people and goods rely on every day.
Tish Mossman, RELI Group’s Vice President of National Security & Safety, has supported TSA and its mission throughout her career. Her perspective offers a closer look at the scale of the agency’s early work and the changes she has witnessed over time.
The Creation of TSA
The TSA we know today was built in response to an unprecedented moment in U.S. history. In just a matter of months, aviation security shifted from a largely decentralized system to a federal responsibility, reshaping how millions of travelers moved through the nation’s airports.
September 11, 2001: A Turning Point for U.S. Aviation Security
Four commercial aircrafts were hijacked as part of the September 11 terrorist attacks, resulting in the Federal Aviation Administration (FAA) taking the unprecedented step of grounding air traffic across the United States.
The attacks exposed significant vulnerabilities in the nation’s aviation security system and fundamentally approached the threat of hijackings.
In the days that followed, one question changed how the federal government became increasingly urgent: How should the United States secure its aviation system against a threat of this scale?
November 19, 2001: The Creation of TSA
In just 69 days, the United States went from grounding air traffic nationwide to establishing a new federal agency dedicated to transportation security.
As flights gradually resumed after September 11, airport security rapidly intensified. National Guard personnel were deployed to airports, screening procedures were strengthened, and federal leaders debated whether airport screening should remain primarily a private responsibility or shift to the federal government.
On November 19, President George W. Bush signed the Aviation and Transportation Security Act into law, formally establishing TSA and marking a major shift in the federal government’s role in aviation security.
For Mossman, the short timeline is striking because of how much TSA had to accomplish.
“What stands out is the magnitude of what had to be accomplished in such a short period of time,” she said. “Bringing together a team to take on the enormous responsibility of protecting our nation’s transportation system was remarkable. TSA had to build an entirely new approach to aviation security, from screening passengers to deploying screening technology across airports nationwide, and do it all with an incredible sense of urgency.”
Following the creation of TSA in November 2001, airport security became a federal responsibility, and the passenger screening experience changed significantly.
| Before TSA | After TSA |
|---|---|
| Screening was conducted by private security companies hired by airlines. | Screening was conducted by federally trained TSA officers. |
| Friends and family could accompany travelers to the gate. | Only ticketed passengers are allowed beyond security checkpoints. |
| Airport security procedures varied by airport and airline. | Standardized federal security procedures rolled out nationwide. |
| Checked baggage was not universally screened for explosives, and carry-ons were not extensively screened. | All checked luggage is screened for explosives, with thorough passenger and carry-on screening. |
2002–2003: Building TSA From the Ground Up
Creating TSA was only the beginning. In 2002, the agency began assuming leadership for aviation security responsibilities previously held by the FAA while building a federal screening workforce from the ground up.
Within its first year, TSA hired and trained tens of thousands of employees and deployed federal screeners to more than 400 airports nationwide. In March of 2003, TSA became part of the newly created Department of Homeland Security, marking another step in the development of the nation’s new approach to transportation security.
The Expansion of TSA
Once the initial screening system was in place, TSA had to continue adapting as new threats emerged. The agency deployed new screening procedures, risk-based programs, and advanced technologies that transformed the passenger experience while strengthening the agency’s ability to identify and respond to evolving risks.
September 2006: New Threats Change What We Carry
After authorities disrupted a terrorist plot involving liquid explosives, TSA introduced new restrictions on liquids in carry-on baggage. The resulting 3-1-1 rule became one of the most recognizable changes to airport screening, limiting travelers to small containers of liquids packed within a single clear bag.
The rule remains a familiar part of air travel today and demonstrates how a specific security threat can lead to lasting changes in the passenger experience.
December 2011: TSA PreCheck® Introduces Risk-Based Screening
TSA began piloting TSA PreCheck in 2011, marking an important shift toward risk-based security. The program allowed eligible, lower-risk travelers to receive expedited screening while enabling TSA to focus resources more effectively based on risk.
The program also reflected TSA’s growing focus on improving the passenger experience without compromising security.
2010s–2020s: Technology Transforms the Checkpoint
As threats and technology continued to evolve, TSA modernized screening both at the passenger checkpoint and behind the scenes. Travelers began encountering new technologies for screening carry-on bags and verifying identities, while checked baggage systems also advanced to detect potential explosive threats before bags were loaded onto aircraft.
Mossman remembers how different the earliest TSA checkpoints were for passengers.
“In the early days of TSA, travelers would stand in security lines for three hours to be screened, have their government ID reviewed and their baggage scanned,” she said. “It was dramatic, going from minimal security just three weeks earlier.”
As TSA built its workforce and infrastructure, those wait times gradually decreased. Today, Mossman said, the average TSA checkpoint processes travelers in less than 15 minutes.
| Early TSA Checkpoints (2000s–2010s) | TSA Checkpoints Today (2020s) |
|---|---|
| 2D X-ray images | 3D imaging lets officers virtually rotate and inspect bag contents without opening luggage. |
| Manual ID checks | Credential Authentication Technology verifies IDs electronically. |
| Heavy reliance on physical documents | Digital identity technology is available at select checkpoints. |
| Standardized screening for 100% of passengers | Risk-based screening helps tailor security procedures. |
TSA introduced increasingly advanced tools, including computed tomography (CT) scanners for 3D imaging, credential authentication technology and enhanced identity verification capabilities. These technologies strengthen threat detection while helping TSA process passengers more efficiently and improve the checkpoint experience.
TSA Today
As TSA approaches its 25th anniversary, the agency continues to evolve beyond the security processes established in its early years. Recent changes reflect a growing focus on identity verification, technology and security across an increasingly complex transportation system.
May 7, 2025: REAL ID Enforcement Begins
On May 7, 2025, federal REAL ID requirements went into effect at TSA checkpoints. Travelers 18 and older were required to present a REAL ID-compliant license or another acceptable form of identification for domestic air travel, strengthening identity standards at the checkpoint.
February 1, 2026: TSA ConfirmID Launches
On February 1, 2026, TSA launched TSA ConfirmID, a modernized alternative identity verification process for travelers who arrive without a REAL ID or another acceptable form of identification. The new process represents another step in TSA’s continued modernization of identity verification and checkpoint security.
November 19, 2026: TSA turns 25
Twenty-five years after its creation, TSA’s mission reaches beyond the airport checkpoint. The agency helps secure aviation as well as mass transit, rail, highways, pipelines and other transportation systems while responding to evolving physical and cybersecurity threats.
From an agency created just 69 days after September 11 to today’s technology-enabled transportation security organization, TSA’s history has been defined by its ability to adapt.
Beyond the Airport Checkpoint
While aviation security is arguably TSA’s most visible responsibility, it represents only one part of the agency’s broader mission. TSA is responsible for protecting all forms of transportation into, out of, and across the country, whether by highway, railroad, public transit, pipeline or port.
That broader mission is what makes TSA’s evolution relevant beyond the airport. These transportation systems support daily travel, commerce and the movement of essential goods across the country. Protecting them requires TSA to continue adapting as threats and technologies change.
For RELI, supporting that work means contributing to a mission that affects both national security and daily life.
“Supporting TSA’s mission alongside its dedicated workforce has been an honor for RELI,” Mossman said. “We’re proud to know that our team plays a role in protecting our nation’s transportation systems and helping ensure the freedom of movement for people and commerce.”
As TSA approaches its 25th anniversary, its history offers a look at the work behind a transportation system millions rely on every day. From airport checkpoints to transportation networks across the country, TSA continues to evolve so people and goods can move safely through systems that are secure, connected and prepared to meet changing needs.
