What The TSA Liquids Rule Really Means At US Checkpoints In 2026

The Transportation Security Administration (TSA) restriction on liquids, aerosols, and gels, widely known as the 3-1-1 rule in the United States, was not an arbitrary policy. Because legacy X-ray machines could not safely differentiate harmless beverages or toiletries from volatile liquid explosive components, it was implemented by the TSA in August 2006. The decision followed a counterterrorism operation in the United Kingdom where intelligence thwarted a plot by terrorists to board transatlantic flights and detonate explosives disguised inside soda cans. Since then, advanced Computed Tomography (CT) scanners have improved the screening experience, even as regulations remain the same. The machine's software can automatically calculate liquid density and identify hazardous substances packed deep inside luggage. CT allows TSA officers to rotate a bag's image a full 360 degrees, dissecting complex internal layers. Today, some airports in the UK and Europe now allow liquids up to two liters. However, the US network has yet to lift the 3-1-1 restriction because advanced scanners have not yet reached nationwide deployment. The TSA will not lift the 3.4-ounce (100 ml) restriction nationwide until CT scanners are deployed at 100% of airports. To prevent security gaps and avoid confusing travelers moving between upgraded and non-upgraded domestic airports, the TSA is keeping the rule as the national standard. Once every airport in the country is equipped with the same machines, a new liquid policy is expected to follow. 3-1-1: The Rule That Never Left Credit: Elliott Cowand Jr | Shutterstock Contrary to speculation among some Americans that it was lifted, the TSA liquids limit remains unchanged today. This misconception stemmed from the introduction of new screening technology, specifically CT scanners. Even with the rollout, travelers are still limited to a single clear, quart-sized plastic bag per person to hold three volume-compliant liquid containers. Beyond being a mnemonic, the 3-1-1 rule continues to be the guiding principle that dictates the total amount that is allowed. Despite the rule's inconvenience and unpopularity, any modification depends on technological advances that allow reliable fluid identification. The restriction has evolved since its inception. After the complete ban in 2006, the rule transitioned to the small-bottle and quart-bag limit on September 26, 2006. The change reflected a shift from a three-ounce limit to 3.4 ounces to align with the international standard of 100 milliliters. As of late 2026, over 1,100 million-dollar CT units have been deployed across 300 major domestic airports. However, the remaining third of the network, comprising hundreds of smaller regional lanes, still depends entirely on legacy 2D X-ray infrastructure. Meanwhile, one public statement from a government official in 2025 triggered rumors about the potential lifting of the rule. Credit: US Government On July 8, 2025, the Department of Homeland Security ended the routine passenger shoe-removal requirement, according to CBS News. The sudden, total elimination of this 20-year-old protocol sparked widespread confusion among the flying public. As the signature post-9/11 hassle vanished overnight, it primed passengers to believe that a complete dismantling of all historical checkpoint rules was imminent. This climate of high expectations set a trap for widespread public confusion just eight days later. On July 16, 2025, then-Secretary Kristi Noem spoke at a conference hosted by The Hill and explicitly singled out the standing policy. By musing that container volume increases would be "the next big announcement," she inadvertently caused millions of travelers to coordinate internal review with immediate policy changes. Numerous outlets rapidly repeated her optimistic outlook, envisioning one-minute checkpoint walkthroughs directly to the aircraft gate. However, Noem provided no real details or concrete deployment timelines for a 3-1-1 rule overhaul. Former TSA Administrator John Pistole later confirmed that the agency had quietly evaluated liquid-restriction rollbacks for years. The general public was led to believe that the technology had been put in place to support Noem's sweeping statement. Yet, more than a year later, the strict 3-1-1 mandate remains unchanged and fully enforceable at every US security checkpoint. Analysts say the core issue driving traveler confusion is that dropping the shoe mandate required no new equipment. What A CT Lane Actually Changes For Flyers Credit: Gdisalvo | Shutterstock The TSA prioritizes security enhancements over passenger convenience, as Peter Duffy, the agency's federal security director for Alaska, clarified in a July statement, that CT implementation significantly augments threat-detection capabilities. A checkpoint CT scanner operates on the same technological principles as a medical CT unit, using multiple X-ray perspectives of luggage on a conveyor belt to construct a three-dimensional model. That 3D output lets automated threat-detection algorithms flag potential hazards while agents rotate and inspect the imagery. These scanners have been in deployment for several years. AFAR reported that the TSA began field tests of new scanners at a small number of airports in 2018. Meanwhile, CT units first became operational at Dallas/Fort Worth International Airport (DFW) in November 2017, according to View from the Wing. While sources disagree on the first deployment dates, both outline nearly a decade of operational development behind a technology that many passengers encountered for the first time this year. For travelers, the main advantage of CT is keeping laptops and liquids inside their luggage, as AFAR remarked. However, the new CT scanners are limited to luggage that can actually fit through the machine. A TSA spokesperson was quoted by the Hill, saying the new units cannot accommodate certain large carry-on bags. AFAR noted that while CT scanners are currently being integrated into many PreCheck lanes, flyers with bags that do not fit will be asked to go to secondary screening stations. Screening procedures also remain inconsistent within individual airport terminals. AFAR advised passengers to follow local rules because many facilities operate a mix of conventional two-dimensional X-ray and advanced CT lanes. In either case, the 3-1-1 restriction still remains fully enforceable, matching the protocol of standard lanes. Consequently, the primary operational variable for air travelers remains the statistical likelihood of encountering a CT-equipped checkpoint during their transit. A Rollout Counted In Airports, Not Lanes Credit: Tada Images | Shutterstock The fundamental, insurmountable obstacle to full-scale deployment of PT scanning technology at US airports is the massive scale of the national network. The TSA is tasked with securing approximately 2,000 screening lanes across 430 airports nationwide. A comprehensive, nationwide technology overhaul requires billions in capital. Until the entire country has a uniform network of equipment, it must maintain legacy policy to enforce the same standard from coast to coast. By July, the agency successfully hit a baseline of 1,162 advanced CT units across 296 domestic airports. On August 24, the TSA officially launched its 'Horizon 25 Strategy.' This decade-long modernization roadmap explicitly re-prioritizes the agency's goals. The core pillars of the plan focus on integrating three technologies simultaneously to overhaul lanes: next-generation CT scanners, upgraded Advanced Imaging Technology (body scanners, and Credential Authentication Technology units. The 3D CT scanner gantries are massive, heavy machines that require a completely redesigned footprint. Many older terminal checkpoints lack the physical square footage or floor-load capacity to house them without extensive remodeling. Total network deployment requires the TSA to cover roughly 2,000 screening lanes across 430 federalized airports. According to current DHS budget projections, the target timeline to reach Full Operational Capability for these property screening systems has been formally pushed out to fiscal year 2034. Current funding earmarks roughly $192 million per year for the procurement and deployment of these Checkpoint Property Screening Systems. Because each machine requires significant capital to buy, test, and maintain, this localized funding rate prevents the TSA from purchasing the thousands of units needed for immediate rollout. While the US rollout remains a multi-decade project, the UK has moved much faster. What Heathrow Did That Washington Has Not Credit: 1000 Words The rollout across the UK and the European Union has moved at a drastically different pace than in the US, but both regions have faced unique logistical and regulatory roadblocks. In January, London Heathrow Airport (LHR) completed a comprehensive £1 billion security modernization program. LHR replaced every passenger checkpoint lane across all four active terminals with advanced CT scanners and officially scrapped the 100ml liquid limit. A select group of major UK airports has fully completed the transition alongside Heathrow. As of late 2026, Gatwick, Edinburgh, Birmingham, Bristol, and Belfast also allow the 2-liter limit. Conversely, major gateways like Manchester, London Stansted, and Luton missed their infrastructure deadlines and still enforce the legacy policy. The UK Department for Transport initially aimed to eliminate the 100ml rule nationwide by 2024, but the reality has become a fragmented 'patchwork' map. The European Commission originally cleared the way for EU member states to drop liquid limits on an airport-by-airport basis as they installed certified next-generation C3 scanners. However, across the English Channel, the European Union hit a regulatory roadblock. Conflicting progress among the US, UK, and EU has created a major pitfall for international travelers known as the 'Return-Flight Trap.' Security rules follow your departure airport, not your airline or passport.