What is security screening?

What happens at a TSA security checkpoint?

Passenger screening is part of TSA's layered approach to aviation security, and the checkpoint is the boundary that keeps prohibited items out of the sterile area, the part of the airport beyond it. TSA says it screens approximately 3.3 million carry-on bags a day for explosives and other dangerous items. [1]

Travellers show identification, then put their belongings through X-ray screening. Personal electronic devices larger than a cell phone — laptops, tablets, e-readers and handheld game consoles among them — have to come out of the bag and go into a bin with nothing placed on or under them, while hair dryers, electric shavers and electric toothbrushes do not have to be removed. [1] Officers may also ask travellers to separate foods, powders and any materials that clutter a bag and obstruct clear X-ray images. [1] Food such as fruit, health bars and sandwiches can usually stay inside the carry-on bag. [1]

Electronic devices, including cell phones, may have to be powered up: a device without power will not be permitted on board, and TSA says it does not read or copy information from the device. [2]

People are screened with millimetre wave advanced imaging technology and walk-through metal detectors. [1] Advanced imaging technology checks for metallic and non-metallic threats without physical contact, uses non-ionizing radio-frequency energy in the millimetre spectrum rather than X-rays, and shows potential threats on a generic outline identical for every passenger instead of a passenger-specific image. [1] Passengers can generally decline advanced imaging technology in favour of physical screening, but a limited number whose boarding passes show selection for enhanced screening must go through it. [1] Anyone wearing a light outer garment or bulky clothing is asked to remove it before screening. [1]

What identification do you need at the TSA checkpoint?

Adult passengers 18 and older must show valid identification at the airport checkpoint in order to travel. [4] Accepted forms include state-issued REAL ID-compliant driver's licences and identification cards, U.S. passports and passport cards, DHS trusted traveller cards such as Global Entry, NEXUS, SENTRI and FAST, permanent resident cards, foreign government-issued passports, Transportation Worker Identification Credentials and Veteran Health Identification Cards. [4] A temporary driver's licence is not accepted. [4]

Since 7 May 2025, state-issued driver's licences and IDs that are not REAL ID compliant are no longer accepted at airports, so travellers without one need an acceptable alternative such as a passport. [4] TSA currently accepts expired ID up to two years after expiration for the forms on its list. [4] From 1 February 2026, a traveller who cannot provide an acceptable form of ID has the option to pay a $45 fee to use TSA ConfirmID, after which TSA attempts to verify identity so that screening can begin. [4]

Children under 18 do not need identification when travelling within the United States, except that unaccompanied minors eligible for TSA PreCheck must show an acceptable ID to receive expedited screening. [4] If identity cannot be verified, the traveller will not be allowed to enter the screening checkpoint. [4]

How does TSA PreCheck change the checkpoint?

Standard screening requires removing all items and placing them on the X-ray belt. In a TSA PreCheck lane, eligible travellers do not need to remove shoes, laptops, liquids, belts and light jackets. [1] [6] The programme provides five years of benefits for $85 or less in dedicated lanes across the United States; TSA says about 99% of passengers wait less than 10 minutes in them, and children 17 and under can join an adult in the lane free of charge. [6]

Enrolment runs through three authorised providers — CLEAR, IDEMIA and Telos — which together operate over 1,300 enrolment locations. [6] Applicants start the application online, finish in person with a document check, fingerprints and a photograph, then enter the Known Traveler Number in airline reservations so the indicator appears on the boarding pass. [6]

Why might a passenger be asked to undergo a pat-down?

Pat-down procedures are used to determine whether prohibited items or other threats are concealed on a person. A traveller may be required to undergo one if the screening technology alarms, as part of unpredictable security measures, for enhanced screening, or as an alternative to other types of screening such as advanced imaging technology — and even passengers who normally receive expedited screening, such as TSA PreCheck passengers, may at times receive a pat-down. [1]

A pat-down may include the head, neck, arms, torso, legs and feet, including head coverings and sensitive areas such as breasts, groin and buttocks, and clothing may need to be adjusted. [1] Officers use the back of the hands over sensitive areas, with front-of-hand screening reserved for limited cases, and the pat-down is carried out by an officer of the same sex. [1] Travellers can request private screening with a companion of their choice at any point, with a second officer of the same sex always present, and can ask for a chair if needed. [1]

Exceptions and limits

• No item is guaranteed passage. An item that is generally permitted may still be subject to additional screening or be refused if it triggers an alarm, appears to have been tampered with or raises other security concerns, and the final decision rests with the TSA officer. [2]
• Liquids that alarm. Any liquid, aerosol, gel, cream or paste that alarms during screening requires additional screening. [5] Medications and infant and child nourishment are exempt from the 3.4 oz (100 ml) container limit. [5]
• Duty-free exception. Liquids over 3.4 oz (100 ml) bought duty free may stay in the cabin when purchased internationally on a trip to the United States with a connecting flight, provided the retailer packed them in a transparent, secure, tamper-evident bag that shows no signs of tampering, the original receipt is present and the purchase was made within 48 hours; the items must still be screened and cleared. [5]
• Flights to the United States. Travellers departing from last-point-of-departure airports into the United States may face more extensive screening of their property and personal electronic devices, and TSA recommends arriving early; the items allowed in carry-on and checked baggage do not change. [1] TSA encourages packing powders over 12 oz (350 mL) in checked bags, because powders in carry-on baggage may require secondary screening and powders that cannot be resolved by security officials have been prohibited from the cabin since 30 June 2018. [1]
• Checked baggage. Checked bags are screened separately, about 1.3 million a day, and most are cleared without a physical bag search; when a bag is inspected, TSA leaves a notice of baggage inspection inside it. [1]

Frequently asked questions

Do you need an ID to get through a TSA checkpoint?

Yes. Passengers 18 and older must show valid identification at the checkpoint in order to travel, from a list that includes REAL ID-compliant state licences, passports and DHS trusted traveller cards. [4] Children under 18 do not need ID for travel within the United States. [4]

Can you take liquids through security?

Yes, in containers of 3.4 oz (100 ml) or less packed in a single quart-sized bag. [5] Anything larger belongs in checked baggage unless it falls under the medication, infant and child nourishment or duty-free exemptions. [5]

Does TSA PreCheck mean you skip security screening?

No. PreCheck changes what you have to remove — shoes, laptops, liquids, belts and light jackets can stay — but all travellers are screened and no individual is guaranteed expedited screening. [1] [6]

Can you ask for a private pat-down?

Yes. At any time during the process a traveller may request private screening accompanied by a companion of their choice, and a second officer of the same sex is always present. [1]

What happens if a permitted item sets off an alarm?

It may be screened again or kept out of the cabin. Liquids, aerosols, gels, creams and pastes that alarm require additional screening, and any permitted item that triggers an alarm, appears tampered with or raises other security concerns can be refused at the checkpoint. [2] [5]

Related pages

Terms: airport liquids rule, prohibited items at security, airport fast track. Browse the full frequent flyer glossary.

Sources

Sources accessed on 18 October 2026. It describes Transportation Security Administration checkpoint rules at airports in the United States; screening in other countries is run by other authorities under their own rules, equipment and exemptions and is not covered here.

1. TSA: Security Screening, checked 18 October 2026
2. TSA: What Can I Bring?, checked 18 October 2026
3. TSA: Acceptable Identification at the TSA Checkpoint, checked 18 October 2026
4. TSA: Liquids, Aerosols, and Gels Rule, checked 18 October 2026
5. TSA PreCheck, checked 18 October 2026