Twenty-five years after the 9/11 attacks, the Transportation Security Administration is charting a new course with its Horizon 25 strategy, aiming to streamline passenger screening. But critics, including a veteran aviation security researcher, caution that the agency's push for convenience may be outpacing the evidence needed to ensure safety.
Sheldon H. Jacobson, a professor of computer science at the University of Illinois Urbana-Champaign, has spent three decades studying risk-based aviation security, including work that underpinned TSA PreCheck. In a recent analysis, he argues that while tightening security is straightforward, relaxing it is fraught with peril. The TSA, he says, must balance security with passenger flow, but recent moves suggest a tilt toward convenience that could introduce unacceptable risks.
One of the most visible changes: the end of mandatory shoe removal for standard screening. That policy emerged after Richard Reid's 2001 shoe bomb attempt. In July 2025, TSA announced that passengers using millimeter wave machines no longer had to remove footwear. However, those machines have limited scanning capability around the feet, and dedicated shoe scanners are still in development. Jacobson points out that no red-team or other test results have been released to show that dropping the shoe rule doesn't create vulnerabilities, making the change premature.
PreCheck passengers have long been exempt from shoe removal, but they undergo background vetting, which lowers their risk profile—a key distinction. The same logic should apply to other relaxations, Jacobson argues. He points to the TSA's remote screening pilot at Framingham, Massachusetts, launched in June 2026, where Delta and JetBlue passengers are screened off-site and bused to Boston Logan. More than 10,000 passengers used it in the first two months, and expansion is being considered. But that facility uses walk-through metal detectors, not millimeter wave scanners, and has documented security risks. Limiting it to PreCheck travelers would have been the safer approach, he says.
Not all changes are problematic. The Gateside by TSA PreCheck program, now at 13 airports, lets vetted passengers pass through checkpoints without flying, formalizing what some airports already allowed. Because it's restricted to PreCheck, the risk is manageable, and adding facial recognition could further mitigate residual threats.
On the technology front, TSA is deploying computed tomography (CT) machines for carry-on bags, which provide 3-D images and make it harder to conceal liquid explosives. This is a precursor to relaxing the 3-ounce liquid rule, as some UK airports have already done. When that happens, Jacobson urges that it be limited to PreCheck passengers, given their reduced risk.
The core problem, he says, is that about 2.5 million people are screened daily, and nearly all are over-screened. The goal should be to find the few risky needles in a vast haystack of benign travelers—focusing on threatening people, not just items. PreCheck is designed to do that, but roughly two-thirds of passengers still use standard lanes.
Jacobson proposes a radical shift: make PreCheck free for anyone willing to undergo background vetting. That would allow all but one lane at each airport to be PreCheck, with a single standard lane for those who opt out or are rejected. The upfront cost would be recouped through reduced staffing, lower technology costs, and higher throughput, while maintaining short wait times to keep travelers engaged.
Such a system, he argues, would be both more convenient and more secure. But it hinges on TSA's willingness to prioritize risk-based screening over blanket procedures. As the agency rolls out Horizon 25, the question remains whether it can navigate this balance without compromising the safety that has defined air travel since 9/11.
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