Now that TSA has ended the shoe-removal policy at screening lanes, rules related to laptops, liquids, jackets and belts are likely to receive consideration in the months and years ahead.
"Every rule is being evaluated," Department of Homeland Security secretary Kristi Noem stated on July 8, as she announced the change related to shoes.
The U.S. Travel Association is pleased.
"We commend Kristi Noem's leadership to reexamine screening practices that are no longer needed once the right technology is in place," U.S. Travel said in a statement. "Her remarks suggesting that changes to liquid restrictions may be next show a clear commitment to modernizing air travel through risk-based decision-making and advanced screening technology."
In February, U.S. Travel called for the U.S. to have the world's most advanced and secure airport-screening process, with technology that strengthens security and reduces wait times. It wants a system that allows travelers to carry filled water bottles through security and to allow them to leave all electronics in their bags. CEO Geoff Freeman said "the status quo is not an option" because the U.S. risks losing visitors if lines are long and the hassle factor is high.
Airport security experts, meanwhile, would like to know with more certainty what led TSA to determine that the requirement that passengers remove shoes is no longer necessary.
"I want to make sure that the decision wasn't motivated by politicians," said Jeff Price, a professor at Metropolitan State University in Denver, and a former assistant security director at Denver Airport. He noted efforts by Sen. Mike Lee (R-Utah), who along with Sen. Tommy Tuberville (R-Ala.), filed a bill that would replace TSA with privatized airport security.
In her remarks, Noem said that advancements in screening technology over the past several years, aided by this spring's implementation of the Real ID requirement, allowed TSA to determine that shoe removal is no longer necessary.
Though Noem's comments lacked detail, TSA now uses millimeter wave scanners at 382 of the 432 federalized airports, including all larger airports. Those scanners, which most commonly require flyers to stand facing the side with their hands in the air, have replaced x-ray machines and scan individuals from head to toe. They offer visibility inside shoes, though large footwear, such as boots, can present challenges that require agents to ask for their removal.
Shoe-removal policies went into place after British national Richard Reid attempted to detonate bombs in his shoes on an American Airlines flight in 2001.
TSA is far from a trailblazer on eliminating the requirement. Many countries have abandoned shoes-off rules. And through TSA PreCheck, pre-vetted U.S. travelers have long been able to go through security in their footwear, along with the elderly and children.
The TSA is 'rudderless'
University of Illinois computer science professor Sheldon Jacobson, whose research included the foundational analysis of what became the PreCheck program, said that changing the shoe-removal rule probably makes sense. But he reserved a full endorsement due to the lack of detail provided by Noem, and also out of concern that such a significant change was made while there is neither a Senate-confirmed TSA administrator nor an acting administrator appointed by the White House.
Jacobson said TSA relies on layered security. Real IDs, by providing the agency with more certainty on a person's identity, are an enhancement. Nevertheless, a policy change can impact those layers.
He compared the TSA without an administrator to a boat with no rudder.
"When you're rudderless and make changes, once you're on the high seas you're going to be in trouble," he said.
Such holistic considerations, however, may not be a concern of key TSA critics, who have accused the agency of being hesitant to change.
A primer that Lee's office put out when he and Tuberville introduced their bill in March to do away with the TSA said the agency's "highly bureaucratic and noncompetitive nature make it slow-moving, perpetually out of date, highly resistant to innovation and modernization, and simply ineffective."
CT scanners are key
The 3.4-ounce limit on carry-on liquids and requirements to take off belts and remove laptops from carry-ons are among the TSA policies subject to evaluation.
The TSA generally allows liquids within the 3.4-ounce limit, as well as laptops, to remain in bags when security lanes are equipped with 3-D computed tomography scanners, which uses CT technology, and are deployed in 278 U.S. airports.
CT scanners have the capability to detect explosive agents in liquids. In fact, on the same day Noem repealed the shoe-removal policy, Birmingham and Edinburgh became the first U.K. airports to scrap the liquids limit.
TSA, however, does not expect to complete deployment of CT scanners nationwide until 2043, in part due to funding limitations. Any change prior to then would be controversial.
"It should wait because there's still a lot of airports that don't have that technology and I think that would represent too much of a gap in the system," Price said.
Laptops receive extra scrutiny from TSA because they can be used to conceal bombs, as happened on a 2016 flight by the Somali airline Daallo, which injured two passengers and killed the bomber.
Price predicted the laptop-removal rule could be rolled back quicker than the liquids rule, due to CT scanners and other screening improvements.
Jacobson predicted that belt removal will be the next policy to go, though he also said such a change has the potential to slow down screening since metal belts so frequently trigger the scanners.
He emphasized that improvements and deployments of facial recognition technology will be the most effective way for TSA to make other screening requirements less necessary.
"You'll have such confidence in who that person is that you won't have to physically screen them," he said, comparing the potential benefits to TSA's current known crewmember program.
In the meantime, Jacobson doesn't expect the shoe-removal rollback, or other potential changes, to diminish interest in PreCheck.
"Passing through a metal detector rather than a full body scanner alone is worth the price," he said.