Travelers who rely on carry-on luggage may notice an important change at U.S. airport security checkpoints. The Transportation Security Administration is continuing to deploy computed tomography, or CT, scanners that produce detailed three-dimensional images of what is inside a bag.
The technology can make screening easier in several ways. TSA officers can rotate and examine a 3D image instead of relying primarily on a traditional two-dimensional X-ray view. At checkpoints equipped with the technology, travelers can generally leave laptops and other electronics inside their bags. However, the scanners have also created an unexpected concern: their openings can be smaller than those of older checkpoint X-ray machines.
That means an oversized or heavily expanded carry-on that an airline might otherwise accept could encounter a problem at security. Here is what travelers should understand before heading to the airport.
What Changed With TSA’s New 3D Bag Scanners?
Traditional checkpoint X-ray systems produce two-dimensional images of luggage. TSA’s newer CT equipment takes many X-ray images and uses them to construct a three-dimensional view of the contents.
The technology is similar in concept to medical CT imaging, although it is designed specifically for security screening. TSA officers can manipulate the resulting image to examine objects from different angles. TSA says the technology improves its ability to identify explosives and other potential threats.
The scanners are part of a broader modernization of U.S. airport checkpoints rather than a sudden nationwide rule taking effect on one particular date. Travelers may therefore encounter a CT scanner at one airport and older equipment at another.
| Checkpoint Feature | Traditional X-Ray | Newer CT Scanner |
|---|---|---|
| Image | Primarily 2D | Detailed 3D image |
| Officer can rotate image | Limited compared with CT | Yes |
| Laptop removal | Often required in standard screening | Generally can remain inside the bag when instructed |
| Threat detection | Conventional X-ray screening | Advanced algorithms and CT imaging |
| Large items | Larger scanner opening may accommodate some bulky items | Some oversized items may not fit |
Why Some Carry-On Bags Could Become a Problem
The issue receiving attention in September 2026 is not a new nationwide reduction in airline carry-on allowances. Instead, it involves the physical dimensions of the checkpoint equipment.
A TSA spokesperson confirmed in recent reporting that the CT scanners have a smaller opening than the older scanners. The design is connected to the advanced imaging system and its operating requirements.
For most passengers carrying normal cabin-size luggage, this should not create a problem. The bigger concern is luggage that exceeds an airline’s stated dimensions, expandable suitcases that have been packed beyond their normal depth, and unusually shaped items.
A common maximum carry-on measurement at many U.S. airlines is around 22 by 14 by 9 inches, although travelers should always check their specific airline because baggage policies vary. The Federal Aviation Administration also advises passengers to verify their airline’s limits before packing.
A suitcase advertised as a carry-on is not automatically compliant. Wheels, handles, exterior pockets and expansion compartments can increase its actual dimensions.
Could TSA Make You Check Your Carry-On?
Potentially, yes. If an item cannot physically pass through the available checkpoint screening equipment, it still has to be screened another way before entering the secure area.
Depending on the airport and available equipment, TSA personnel may be able to direct the traveler to another screening option. But travelers should not assume that an alternative scanner will always be available. Recent reports indicate that some passengers with items too large for the CT equipment may need to return to the airline and check them.
This could be especially disruptive after a traveler has already waited in the security line. Checking the bag may mean returning to the ticketing area, dealing with the airline, and going through security again.
It could also create another problem: some belongings that are permitted or recommended in the cabin should not simply be transferred into checked luggage. Spare lithium batteries and power banks, for example, have special aviation safety requirements. Travelers unexpectedly checking a suitcase should review its contents first rather than handing it directly to an airline.
Does This Mean Carry-On Size Rules Have Changed?
No broad TSA carry-on size limit has replaced airline baggage policies. TSA handles security screening, while airlines generally establish their own cabin baggage dimensions and allowances.
That distinction is important. A bag can involve two separate questions:
- Will the airline accept it as a carry-on? Check the operating airline’s dimensions and baggage allowance.
- Can it be screened at the checkpoint? The item must physically work with available security-screening procedures and equipment.
Travelers who stay comfortably within their airline’s published limits are less likely to encounter a problem than passengers carrying oversized or overstuffed luggage.
What Travelers Should Do Before Their Next Flight
The safest approach is simple: measure the suitcase after packing it. Do not rely only on the dimensions printed on the luggage tag or manufacturer’s website.
Include the wheels, handles and bulging exterior compartments when measuring. If an expandable zipper adds several inches of depth, consider leaving it closed for the flight.
Travelers should also avoid packing a carry-on so tightly that its sides noticeably bow outward. Besides potentially increasing the bag’s dimensions, a densely packed suitcase can make screening more complicated.
If you are traveling with unusual equipment, a large musical instrument, medical supplies or another bulky item, check both TSA guidance and the airline’s policy before leaving home. Arriving early is especially important if there is any possibility that the item will require additional screening.
The New Scanners Also Have Significant Benefits
The luggage-size issue should not overshadow why TSA is installing CT technology in the first place.
TSA says the equipment provides enhanced threat detection and gives officers much more detailed views of baggage contents. An officer can manipulate the 3D image instead of immediately opening a suitcase whenever something is difficult to identify.
For travelers, one of the most noticeable benefits is reduced unpacking. At CT-equipped lanes, laptops can generally stay inside carry-on luggage during screening. TSA has also said the technology supports its longer-term goal of allowing more items to remain inside bags.
However, passengers should always follow instructions at the checkpoint in front of them. Airports are in different stages of technology deployment, and procedures can vary by lane. If an officer tells you to remove an item, follow that instruction even if another airport previously allowed you to leave it packed.
What About the TSA 3-1-1 Liquids Rule?
The arrival of more sophisticated scanners does not automatically eliminate the familiar U.S. carry-on liquids restriction.
TSA’s published travel guidance continues to describe the 3-1-1 rule: liquids, aerosols, gels, creams and pastes generally must be in containers of 3.4 ounces (100 milliliters) or less and fit within the permitted quart-size bag, subject to established exceptions such as medically necessary liquids.
In other words, better scanning technology should not be interpreted as permission to pack full-size shampoo, beverages or other ordinary liquids in a carry-on. Follow current TSA rules unless the agency announces otherwise.
Who Should Pay the Most Attention?
Travelers with ordinary backpacks and standard-size cabin luggage are unlikely to need major changes. The warning matters more for people who routinely stretch carry-on limits.
Pay particular attention if you use an expandable roller bag, travel with bulky equipment, routinely overfill a soft-sided suitcase, or have an older carry-on that is larger than today’s common airline dimensions.
The issue also matters for travelers on tight schedules. An unexpected trip back to the airline counter could consume valuable time. If your luggage is questionable, arriving earlier than usual provides some protection against missing a flight.
Frequently Asked Questions
Are TSA’s new scanners actually 3D scanners?
Yes. They use computed tomography to create three-dimensional X-ray images of carry-on contents. Officers can manipulate those images to examine objects from multiple angles.
Will a normal 22-by-14-by-9-inch carry-on fit?
Recent TSA comments reported by news outlets indicate that bags meeting common airline carry-on dimensions should fit. Travelers should still measure the fully packed bag, including wheels, handles and expansion sections, and verify the rules of their particular airline.
Should I check my suitcase just because my airport has CT scanners?
Not necessarily. Standard carry-on luggage remains practical. The main reason for concern is a bag that is oversized, expanded, unusually shaped or packed beyond its normal dimensions.
Can I leave my laptop in my bag?
At checkpoints using CT equipment, TSA says laptops can remain inside the bag during screening. Always follow the instructions given by officers at your particular lane because equipment and procedures can differ.
Do the new scanners mean larger liquids are now allowed?
No. Travelers should continue following TSA’s current liquids rules. New scanning technology does not by itself change what passengers are permitted to bring through a checkpoint.
Bottom Line for Travelers
TSA’s new 3D bag scanners are primarily a security technology upgrade, not a new airline baggage policy. They provide officers with detailed CT images and can make checkpoint screening more convenient by reducing the need to remove certain electronics.
The trade-off is that the scanner opening can be smaller than that of older equipment. For travelers who routinely push carry-on dimensions to the limit, that creates a new reason to measure luggage carefully.
Before your next flight, check your airline’s current carry-on dimensions, measure the bag after packing, avoid unnecessarily expanding it, and leave additional airport time if you are traveling with something bulky. Those few steps can reduce the chance that a trip planned around carry-on-only travel unexpectedly turns into a visit to the checked-baggage counter.
References
- Transportation Security Administration — Computed Tomography — TSA’s overview explains how CT checkpoint technology creates 3D images, improves threat detection and changes the screening of laptops and other carry-on contents.
- Transportation Security Administration — What Can I Bring? — Official TSA guidance for checking whether specific items are permitted in carry-on or checked baggage.
- Transportation Security Administration — TSA Travel Tips — Supports current guidance on the 3-1-1 liquids rule, packing practices and preparing for airport security screening.
- Federal Aviation Administration — Carry-On Baggage Tips — Explains general carry-on planning and advises passengers to verify baggage size and quantity limits with their airline.
- Transportation Security Administration — Checkpoint Requirements and Planning Guide — TSA technical guidance describing current CT checkpoint property-screening systems and their role in producing three-dimensional images of baggage contents.