US Domestic Airline Policies 2026: Size Limits, Fees, Liquids & Banned Items

Quick answer:  Standard carry-on size: 22×14×9 inches including wheels and handles. Southwest allows 24×16×10 inches. Budget airlines charge $35–$99 for carry-ons depending on when you pay. American, Delta, and United Basic Economy: personal item only — no overhead carry-on. Every airline on every fare allows one free personal item (roughly 18×14×8 inches) under the seat.

Carry-on rules have always existed. What is new in 2026 is that airlines are enforcing them — automated bag scanners at gates, proactive jetway checks, and gate agents under explicit pressure to manage bin space. The $99 gate-check fee that used to happen to other people is now happening to everyone with an oversized bag or an unpaid carry-on on a budget airline.

This guide covers every US domestic airline, every fare class, every fee tier, and the two big rule changes that most travelers are still getting wrong: lithium battery enforcement and REAL ID. Every size limit, fee, and restriction below was verified directly from official airline websites in May 2026.

Use the quick-reference table to find your airline fast. Then read the detailed section for anything you need to understand fully. The FAQ at the bottom answers the questions that show up in comments every week.

1. US Domestic Airlines Carry-On Rules at a Glance:

All sizes include wheels and handles at full extension. A suitcase labelled ’22 inches’ by the manufacturer often measures 23.5–24 inches once the telescoping handle and base wheels are included. Measure your packed bag — not the empty shell.

What is the carry-on size limit for US Domestic airlines in 2026?

Airline	Carry-On Size	Fee	Personal Item	Key Rule 2026
American	22×14×9″	Free	18×14×8″	Basic Economy: personal item only
Delta	22×14×9″	Free	18×14×8″	Basic Economy: personal item only
United	22×14×9″	Free	17×10×9″	Basic domestic: personal item only
Southwest	24×16×10″	Always free	18.5×13.5×8.5″	No restrictions — most generous US airline
JetBlue	22×14×9″	Free	17×13×8″	Blue Basic: personal item only
Alaska	22×14×9″	Free	17×13×6″	Saver fare: personal item only
Spirit	22×18×10″	$35–$99	18×14×8″ (free)	Pay at booking — gate fee is $99
Frontier	24×16×10″	$35–$79	18×14×8″ (free)	Gate fee is $79
Allegiant	22×16×10″	$10–$75	18×14×8″ (free)	25 lb weight limit strictly enforced
Sun Country	24×16×11″	$30–$50	18×14×8″ (free)	Bundle fares include carry-on
Hawaiian	22×14×9″	Free	25 lb limit inter-isl.	Smaller bins on inter-island aircraft

How to measure correctly: stand your bag upright on the floor. Extend the handle fully. Measure height (floor to top of handle), width (widest point including all pockets and bulges), and depth (front to back at the deepest point). All three must be at or under the airline’s stated limit simultaneously — not one dimension at a time.

2. How Airline Carry-On Rules Actually Work

The two measurement systems US airlines use

H×W×D in inches — used by American, United, Alaska, JetBlue, and most carriers. The near-universal limit: 22×14×9 inches.

Linear inches — Delta’s preferred format, meaning the sum of all three dimensions. Delta’s limit is 45 linear inches.

Since 22+14+9 = 45, this is identical to the standard limit in practice. The only flexibility: you can slightly redistribute inches across dimensions as long as the total stays at 45.

‘Including wheels and handles’ — why this catches people

Airlines measure the total external footprint of the bag, not the body. The handle extending above the top of the bag and the wheels adding height at the bottom both count.

A 22-inch suitcase (body measurement) is typically 23.5 to 24 inches in total. Always measure your bag fully packed with the handle extended and the bag standing on its wheels before you leave home.

Carry-on vs personal item — the distinction that determines your fee

Every US airline allows two items: one carry-on for the overhead bin and one personal item for under the seat. The personal item is always free on every airline, on every fare class — including Spirit and Frontier and Basic Economy. Fees and restrictions only apply to the carry-on.

• Personal item: fits under the seat. Roughly 18×14×8 inches. Backpacks, laptop bags, totes, small duffels.
• Carry-on: overhead bin. Standard 22×14×9 inches. Rolling suitcases, large backpacks, large duffels.

2026 enforcement shift: agents are now checking that personal items genuinely fit fully under the seat — not just that they look small enough. If it sticks into the aisle, protrudes forward, or requires real force to push under, it gets reclassified as a carry-on. On budget airlines that reclassification costs up to $99.

3. Full-Service Airlines: Detailed Carry-On Rules

American Airlines

• Carry-on: 22×14×9 inches.
• Personal item: 18×14×8 inches.

Both free on every fare except Basic Economy (personal item only). Published weight guideline: 40 lbs — not actively enforced on domestic flights but referenced on international routes.

Basic Economy boarding trap: Basic Economy passengers board last in Group 9. Overhead bins are almost always completely full by then.

This usually results in a free gate-check because there is literally no bin space — not a fee, unless your bag is also oversized or non-compliant.

American Airlines allows one personal item and one standard overhead bag. For a deep dive into weight restrictions and sizer leniency, check out the specific American Airlines carry-on size guide.

Delta Air Lines

• Carry-on: 22×14×9 inches (45 linear inches).
• Personal item: must fit under the seat.
• Basic Economy: personal item only — no overhead carry-on.

Delta Connection regional jets operate with smaller overhead bins — a bag that fits the standard sizer may not fit on a regional aircraft. Always pack a personal item with essentials when your itinerary includes a Delta Connection segment.

Delta deployed automated bag sizer scanners at major hubs in 2025. These flag oversized bags at the gate before boarding with no gate agent discretion involved.

United Airlines

• Carry-on: 22×14×9 inches.
• Personal item: 17×10×9 inches.
• Basic Economy domestic: personal item only.

Exception: United Basic Economy on international routes (transatlantic, transpacific, South America) does include a carry-on.

United expanded automated bag sizers to 35+ airports in late 2025 and is targeting 80+ locations by end of 2026.

These scanners measure carry-ons at the boarding gate and flag non-compliant bags automatically. Bags that always slipped through on visual inspection will now be caught.

Southwest Airlines

• Carry-on: 24×16×10 inches — larger than the US standard.
• Personal item: 18.5×13.5×8.5 inches.

Both carry-on and personal item are free on every Southwest fare including Wanna Get Away. Southwest is the only major US airline with zero carry-on fees and zero Basic Economy carry-on restrictions.

The one real risk: boarding position. Southwest’s open seating means overhead bins fill front-to-back. Travelers in B35 or later on full flights frequently find no bin space left. Buy EarlyBird Check-In or book Anytime or Business Select fares to guarantee early boarding.

Southwest allows a larger bag than any other US airline, charges nothing for it, and imposes no fare-class restrictions. If you fly Southwest regularly, you can size up from the 22-inch standard to a 24-inch carry-on and pay nothing extra.

JetBlue

• Carry-on: 22×14×9 inches.
• Personal item: 17×13×8 inches.
• Blue Basic: personal item only.

All other JetBlue fares (Blue, Blue Plus, Blue Extra, Mint): carry-on included. JetBlue boards window-seat passengers last — even a compliant carry-on may get gate-checked on a full flight without priority boarding. A JetBlue credit card or Even More Space seat provides early boarding access.

Alaska Airlines

• Carry-on: 22×14×9 inches.
• Personal item: 17×13×6 inches.
• Saver fare: personal item only.

Main Cabin and above: carry-on included. Alaska MVP, MVP Gold, and MVP Gold 75K status members board early — the most practical path to guaranteed bin access on Alaska’s often-full West Coast routes.

Hawaiian Airlines

• Carry-on: 22×14×9 inches on mainland routes.

Inter-island flights run on smaller aircraft with smaller overhead bins — verify your specific aircraft before packing. A bag that fits a mainline Boeing 717 may not fit an inter-island ATR turboprop.

Weight limit: Hawaiian enforces 25 lbs on carry-on bags for inter-island flights — stricter than virtually every other US airline, most of which publish no carry-on weight limit. Weigh your packed bag if flying inter-island.

4. Budget Airlines: Fees, Traps, and How to Avoid Both

Warning:  Budget airlines (Spirit, Frontier, Allegiant, Sun Country) do not include a carry-on in their base fares. The fee for adding a carry-on increases significantly the later you pay — up to $99 at the gate on Spirit. Always add the carry-on at initial online booking for the lowest rate. The personal item is always free on all budget airlines.

Spirit Airlines

Carry-on: 22×18×10 inches.

Personal item (always free): 18×14×8 inches, must fit fully under the seat. Spirit uses physical sizer boxes at most gates and checks bags consistently on full flights.

Fee tiers: $35–$55 when added at online booking. $55–$75 at check-in. $99 at the gate. The $99 gate fee is not a rumour — it is a deliberate part of Spirit’s revenue model. Thousands of travelers pay it daily because they did not add the bag at booking. One click at checkout prevents it.

Zero-fee strategy: pack everything into an 18×14×8-inch personal item. A compressible soft backpack or duffel holds more than its stated dimensions suggest when packed with rolled clothes and packing cubes. Most travelers can fit 3–4 days of clothing into a compliant personal item with practice.

Frontier Airlines

• Carry-on: 24×16×10 inches.
• Personal item (always free): 18×14×8 inches.

Fee tiers: $35–$45 online at booking. $45–$59 at check-in. $79 at the gate. Frontier enforces sizer boxes more consistently than legacy carriers.

Bundle fares: The Works and The Perks include carry-on access. On many routes, a bundle fare costs less than base fare plus carry-on fee plus seat selection added individually. Always compare total cost before assuming the base fare is cheaper.

Allegiant Airlines

• Carry-on: 22×16×10 inches.
• Personal item (always free): 18×14×8 inches.

Fee tiers: $10–$35 at online booking (cheapest of any US budget carrier when booked early). $35–$50 at check-in. $75 at the gate.

Warning:  Allegiant enforces a 25 lb weight limit on carry-on bags — the strictest carry-on weight limit of any US airline. Most US carriers publish no carry-on weight limit whatsoever. If your Allegiant carry-on exceeds 25 lbs at the gate, you will pay an overweight fee. Weigh your fully packed bag at home before you leave for the airport.

Sun Country Airlines

• Carry-on: 24×16×11 inches (one of the largest carry-on allowances among US carriers).
• Personal item (always free): 18×14×8 inches.

Fee tiers: $30 online. $50 at the gate. Bundle fares include carry-on access. Sun Country is the most lenient of the budget carriers on enforcement.

Avelo Airlines

Avelo has no published weight cap, but passengers must be able to hoist their carry-on into the overhead bin without help. If you can’t manage it solo at the gate, the bag gets checked — with an extra fee attached.equipment.

Avelo Airlines — carry-on specs

• Personal item – 17 × 13 × 9 in — free
• Carry-on – 22 × 14 × 9 in
• Weight limit – Must lift unassisted into overhead bin
• Fee range – $40 – $65 depending on timing

Free items: Manual wheelchairs, mobility aids, assistive devices, outerwear, musical instruments, and special

Breeze Airways

Breeze ticket bundles fold carry-on access into the fare price. Before booking a base fare and paying $35+ for a bag separately, compare the bundle fare total — it sometimes closes the gap entirely.

Breeze has not published a list of exempt items. For specific queries about items like instruments or medical equipment, contact Breeze directly before your travel date.

Breeze Airways — carry-on specs

• Personal item – 17 × 14 × 8 in — free
• Carry-on – 22 × 14 × 9 in
• Weight limit – 35 lbs maximum
• Fee – From $35 (free with ticket bundle)

5. Lithium Batteries and Smart Luggage: The 2026 Rules

📥 Migrated content:  This section was previously published as a standalone article at /usa-travel-rules-2026-carry-on-tsa. That URL now 301-redirects to this page. Content has been expanded and updated with current FAA enforcement guidance.

Lithium battery rules have existed since 2018. What changed in 2026 is consistent enforcement. Gate agents are trained to check smart luggage batteries.

TSA checkpoints flag power banks in checked bags routinely. And if your carry-on is gate-checked at the last minute, a power bank inside it triggers a mandatory bag retrieval before the aircraft door closes.

The core rule: all spare batteries go in carry-on only

This is an FAA safety rule, not an airline preference. It applies on every US airline, on every flight, with no exceptions.

• Spare lithium-ion batteries (power banks, camera batteries, spare laptop batteries): carry-on only. Never in checked luggage.
• Devices with batteries installed (laptops, phones, cameras): allowed in carry-on AND checked luggage.
• Power banks during flight: must be in your personal item or carry-on bag — not in an overhead bin unattended unless it is in the bag. If your carry-on gets gate-checked, remove your power bank first and carry it on your person into the cabin.

Watt-hour limits — the numbers you need to know

Every battery has a watt-hour (Wh) rating on the label. If yours shows only milliamp-hours (mAh) and voltage (V), calculate: Wh = (mAh ÷ 1000) × V. Most power banks use 3.7V lithium-ion cells — so a 20,000 mAh bank is 74 Wh (fine), and a 27,000 mAh bank is roughly 100 Wh (right at the threshold).

Watt-Hours (Wh)	Rule	Where Allowed
Under 100 Wh	No approval needed. Unlimited for personal use.	Carry-on only
101–160 Wh	Airline approval required. Max 2 per passenger.	Carry-on only
Over 160 Wh	Prohibited on all commercial passenger aircraft.	Not permitted

Smart luggage: the hand-removal rule

Any suitcase with a built-in battery must have a battery removable by hand — no screwdrivers, no tools, no Allen keys. Airlines have enforced this since 2018 but are checking it actively at check-in counters in 2026.

• Battery removable by hand: bag is allowed in carry-on or checked. For checked luggage, remove the battery first and carry it in your personal item.
• Battery requires tools to remove: the bag cannot fly on any US airline in any position — not carry-on, not checked. No exceptions and no workarounds.

If you own a smart suitcase with a non-removable battery, the bag needs to be retired. There is no compliant way to fly with it.

The gate-check and power bank situation most people miss

On a full flight, gate agents sometimes ask passengers to gate-check carry-on bags due to bin space running out. This happens after security, at the gate, immediately before boarding.

If your carry-on contains a power bank, you must remove it before handing the bag over. A bag with a power bank inside cannot go into the aircraft hold — even for a 45-minute domestic flight.

Gate agents will not send it down without the battery removed.

ℹ️  The easiest prevention: keep your power bank in your personal item (the under-seat bag), not your overhead carry-on. Your personal item never gets gate-checked. Power bank stays with you, no scrambling required.

6. REAL ID and Airport ID Requirements in 2026

Migrated content:  This section was previously published at /usa-travel-rules-2026-carry-on-tsa. That URL now 301-redirects here. The information below has been updated with TSA’s February 2026 Confirm.ID fee details.

REAL ID enforcement for domestic US flights became active on May 7, 2025. As of 2026, TSA applies it consistently at all checkpoints.

A standard driver’s licence without the compliance star is no longer accepted. Your options are a REAL ID-compliant licence, a passport, a military ID, or a DHS trusted traveler card.

Accepted ID at TSA checkpoints for domestic flights

• REAL ID-compliant driver’s licence — look for a gold or black star in the upper right corner. No star means it is not REAL ID compliant and will not be accepted.
• US passport book or passport card.
• US military ID.
• DHS trusted traveler cards: Global Entry, NEXUS, SENTRI, FAST.
• Enhanced Driver’s Licences issued by Washington, Michigan, Minnesota, New York, or Vermont.

The Confirm.ID fee: what happens without compliant ID

If you arrive at a TSA checkpoint without an accepted form of identification, TSA’s Confirm.ID process allows alternative identity verification. Starting February 1, 2026, this process carries a $45 non-refundable fee. The fee covers a 10-day travel window — meaning if your trip is longer than 10 days, you pay again on the return flight.

Paying the $45 does not guarantee you will be cleared. It initiates a verification process that takes additional time — typically 15–30 minutes — during which you are pulled aside from the security lane. The fee is for the service, not for guaranteed passage.

⚠️ Warning:  Do not treat Confirm.ID as a backup plan. Build in an extra 30+ minutes if you will be using it. The most reliable approach is still: get a REAL ID star on your licence (a standard DMV renewal in most states) or travel with your passport.

Mobile driver’s licences (mDL) in Apple Wallet or Google Wallet

TSA accepts mobile driver’s licences at select airports and select checkpoint lanes in 2026. The rollout is partial — not all airports support it, not all lanes within supported airports support it, and software failures do occur.

Always carry a physical REAL ID-compliant licence or passport as a backup. Do not arrive at an airport with no physical ID and a phone as your only fallback.

Minors travelling domestically

TSA does not require children under 18 to show identification for domestic flights when travelling with an adult. Airlines may have separate identification requirements for unaccompanied minors — verify with the specific airline before booking.

7. What Changed in 2026: How Enforcement Is Different

The rules themselves have not changed. What changed is the tools, the incentives, and the consistency with which the same rules that existed in 2022 are now applied.

Automated bag sizer scanners

United deployed automated carry-on measurement scanners at 35+ US airports in late 2025 with plans for 80+ by year-end 2026.

American Airlines and Delta are running pilots at major hubs. These scanners measure every carry-on bag at the boarding gate before passengers board — there is no visual judgment from a gate agent.

Before automated scanners: a slightly oversized bag might pass if it looked roughly right and the agent was busy. After automated scanners: a bag that exceeds the limit by half an inch gets flagged. Bags that passed every flight for years will now be stopped.

On-time performance pressure and bin space enforcement

US airlines updated internal boarding guidance in 2025 to link carry-on enforcement directly to on-time departure performance metrics.

Slow boarding from passengers fighting oversized bags into bins, blocking aisles, and rearranging other passengers’ luggage costs airlines FAA performance ratings and airport slot allocations at congested hubs.

The practical result: gate agents on full flights are under active instruction to check carry-ons proactively and pull visually oversized bags before boarding begins — not after the aisle becomes a rugby scrum.

Jetway checks — the enforcement point nobody expects

You have scanned your boarding pass. You are walking down the jetway. You assume you are through. Jetway enforcement is where an increasing share of carry-on flags now happen on packed flights.

A gate agent or flight attendant at the top of the jetway stops bags that appear oversized before passengers reach their rows.

On a completely full flight where overhead bins are pre-assigned, this is nearly unavoidable for borderline bags.

The only reliable prevention: board early. On full-service airlines, pay for priority boarding or use elite status. On budget airlines, pay for a front-of-cabin seat with early boarding access.

The personal item ‘must disappear under the seat’ standard

Airlines have always required that personal items fit under the seat. In 2026, they are checking. The new practical standard across most major US carriers: the personal item must slide fully under the seat with no protrusion into the aisle and without requiring force or diagonal placement.

A large structured tote that technically meets the dimension limit but sticks out 3 inches into the aisle is being called a carry-on.

✅  The clearest test: push your personal item under an economy seat so both ends are fully under the seat bottom and nothing extends into the aisle or blocks foot space. If it slides under easily and disappears completely, it passes. If you have to compress it, angle it diagonally, or push it in multiple stages, it is borderline and will increasingly be flagged on busy flights.

8. tSA carry on restrictions That Affect Your Carry-On

3-1-1 liquids rule — unchanged, but partially superseded at CT airports

The rule has not changed at standard X-ray checkpoints: all liquids must be in containers of 3.4 oz (100 ml) or less, placed in one clear quart-sized zip-top bag, one bag per passenger, removed from your carry-on and placed flat in a tray.

At airports with CT (computed tomography) 3D scanners — now active at ORD, DFW, MIA, LAX, ATL, and a growing list of major hubs — you do not need to remove liquids from your bag. TSA officers will tell you at the lane entrance whether removal is required.

ℹ️  If you are unsure whether your checkpoint has a CT scanner: pack as if it does not. Remove liquids and put them in a tray. If the scanner does not require it, you get waved through quickly. If you assume CT and are wrong, you slow down the entire lane behind you.

Before you pack your toiletries, read our TSA Liquid Rules in 2026: What’s Actually Changed at Airport Security— it covers CT scanner airports, exceptions, and exactly what gets confiscated.

Electronics at the checkpoint

At standard checkpoints: laptops and tablets (iPad-size and larger) must be removed from your bag and placed flat in a separate bin. Phones, cameras, and small electronics can stay in your bag.

With TSA PreCheck ($78 for 5 years, approximately $15/year): all electronics and all liquids stay in your bag at any PreCheck lane.

The average PreCheck wait time is under 5 minutes versus 15–30 minutes in standard lanes. For anyone flying twice or more annually, PreCheck is the single most practical airport investment.

Prohibited items most commonly confiscated

Liquids over 3.4 oz including full-size sunscreen, shampoo, or any oversized toiletry. Scissors with blades over 4 inches. Multi-tools and pocket knives of any size. Sporting equipment including bats, clubs, and sticks. Items resembling weapons including replica firearms and inert grenades. Full current list: tsa.gov/travel/security-screening/whatcanibring.

Frequently Asked Questions

Related Guides on Travel Bag Insider

• Gate-Check Proof Carry-On Bags: 8 Bags Tested in 29 Sizers
• American Airlines Carry-On Size Guide 2026 
• How Strict Are Airlines About Carry-On Size? 
• How to Avoid Gate-Check Fees: 10 Packing Tricks
• International Airlines Hand Luggage Size Chart 2026
• Best TSA-Approved Carry-On Luggage 2026
• What Counts as a Liquid at TSA? (The Complete 2026 List)

source- https://www.tsa.gov/