Airline baggage rules change by fare family and date. Confirm dimensions and fees on the carrier site for your PNR before airport day.
US-focused carry-on guide for 2026: American, Delta, United, Southwest, JetBlue, Alaska and ULCC rules, basic-economy restrictions, and links to the global size comparison chart.
What are US airline carry-on rules in 2026?
For most US majors, plan a carry-on near 22×14×9 inches plus a personal item that fits under the seat — then verify your exact fare family, because basic economy on American, United, Delta and several ULCCs often removes the free overhead bag. Size for the strictest airline on a multi-carrier trip and treat gate sizers as real, not folklore.
This United States utility page focuses on domestic and US-carrier international departures from hubs such as ATL, DFW, ORD, DEN, LAX, SFO, JFK, EWR, MIA, SEA, IAH and BOS. For centimetre comparisons across ~20 global airlines, use the sibling chart at /guides/airline-carry-on-sizes. Fee bands also live in /guides/airline-baggage-fees-compared.
Fare family is the plot twist Americans still miss. A Main Cabin ticket and a Basic Economy ticket on the same flight can have different overhead-bag rights. Deep comparison sits in /us/guides/basic-economy-compared. A $49 headline that becomes a $49 bag fee at the gate is not a deal — see /us/guides/flight-deals-from-usa.
Packing method still matters more than brand slogans: /guides/carry-on-packing-list and /guides/best-travel-gear cover what fits when the sizer is unforgiving. Soft-sided bags forgive corners better than hard shells.
How do carry-on sizes compare across major US airlines?
American, Delta, United and JetBlue commonly publish cabin bags around 22×14×9 inches; Southwest is often listed near 24×16×10 inches; Alaska is typically near the Big Three box; Spirit and Frontier free bags shrink to personal-item sizes on the cheapest fares. Confirm live pages — marketing inches are not a court order.
US domestic enforcement is usually about the sizer box and bin space, not a kilogram scale. That changes when you connect onto many European, Gulf or Asian carriers that weigh cabin bags at 7–12 kg. If your itinerary leaves the US metal, re-read the global chart before you load a 16 lb (7.3 kg) “personal item” full of souvenirs.
Personal items mean underseat: purse, small backpack, briefcase. A second roller is not a personal item. Strollers and medical devices follow separate airline rules — read those pages if you travel with either.
| Airline | Typical carry-on (verify) | Personal item | Basic / saver watch-out | Strictness vibe |
|---|---|---|---|---|
| American | 22×14×9 in | Underseat | Basic often personal-item only | Sizer + fare family |
| Delta | 22×14×9 in | Underseat | Basic restrictions common | Sizer + fare family |
| United | 22×14×9 in | Underseat | Basic Economy bag limits | Sizer + fare family |
| Southwest | 24×16×10 in | Underseat | Two free checked bags typical — still measure carry-on | More forgiving size |
| JetBlue | 22×14×9 in | Underseat | Blue Basic limits overhead | Sizer-focused |
| Alaska | ~22×14×9 in | Underseat | Saver fare rules | Check fare tile |
| Spirit | Personal item free on base | Small underseat | Carry-on is a paid add-on | Very strict |
| Frontier | Personal item free on base | Small underseat | Carry-on is a paid add-on | Very strict |
| Hawaiian / others | Check route pages | Underseat typical | Partner codeshares vary | Verify operating carrier |
How does basic economy change US carry-on rights?
On several US majors, basic economy is a personal-item fare unless you pay to add a carry-on or status/credit-card perks restore one. ULCC base fares work the same way by design. Never assume the overhead bin is free because the aircraft looks identical to Main Cabin.
Status and co-brand cards sometimes restore a bag — that is a perk spreadsheet, not a public promise for every PNR. Read the fare rules after login. Full comparison: /us/guides/basic-economy-compared.
Gate agents have little patience for “I didn’t know.” Prepay the bag in the app if you need the roller; airport prices are usually worse. If bins are full even on a fare that includes a carry-on, your bag may still be gate-checked free on some carriers — that is not a plan for lithium batteries and breakables.
How strict are Spirit, Frontier and other ULCC carry-on rules?
Ultra-low-cost carriers typically include only a small personal item in the base fare and sell the larger carry-on as an ancillary. Their sizers are real and used. If you will not travel personal-item-only, add the bag when the fare is still cheap — or book a different carrier whose Main Cabin already includes the roller.
ULCC maths pairs with /guides/cheap-flights-21-ways: compare all-in cost after bags and seats. A $39 Spirit hop plus a $45 carry-on is a $84 fare before seats. Families with two rollers rarely win on the cheapest tile.
Measure the free personal item dimensions on the airline site — “personal item” on Spirit is not a standard school backpack stuffed like a mule. Soft cubes help; expandable hard shells do not.
Do US carry-on rules change on international flights?
The US marketing size may still apply on American metal, but partner-operated flights and foreign connections can introduce weight caps and smaller free bags. Always size for the strictest segment. Transatlantic basic fares can be especially punitive on overhead bags.
Example pattern: a Dallas–London AA flight with a domestic codeshare feeder — pack to whichever segment publishes the harsher rule. European ULCC connections after a US long-haul are where Americans learn centimetres the hard way; keep /guides/airline-carry-on-sizes open.
Power banks stay in the cabin. Liquids still follow TSA 3-1-1 on departure from the US. Global Entry does not resize your suitcase — /us/guides/tsa-precheck-global-entry-clear.
How do you pack so a US sizer actually passes?
Choose a bag that fits your strictest published box empty, keep unstructured soft sides, wear the heaviest shoes and jacket, and move dense tech into a true underseat personal item. Weigh at home if any international segment publishes kilograms. Do not arrive counting on an empty bin and a friendly agent.
Tape-measure ritual: wheels down, handle in, pockets emptied of water bottles that push you over. If it is snug at home, it will fail at a rigid sizer. The packing-list 5-4-3-2-1 clothing rule exists for this airport moment.
Lounge access does not waive sizers — /guides/airport-lounge-access-guide. Neither does boarding group A if the bag is simply too big.
- Measure including wheels and handles
- Pack to the strictest airline on the ticket
- Prepay bags on basic/ULCC fares if you need a roller
- Soft bags > overstuffed hard shells for sizers
- Screenshot fare bag rules before leaving home
Which US carry-on questions come up most?
Assume 22×14×9 inches on most US majors, read basic-economy fine print carefully, prepay ULCC cabin bags when you need a roller, and use the global size guide when partners abroad weigh bags. The live fare tile beats last year’s TikTok advice every time.
Recheck rules the week you fly — airlines tweak basic bundles without a press tour.
- Standard Big Three size? — Often 22×14×9 in.
- Southwest? — Often larger published size + free checked bags.
- Basic economy roller? — Frequently not free.
- Weight on domestic US? — Fit usually matters more than kg.
- Global chart? — /guides/airline-carry-on-sizes
- Best deal check? — All-in fare after bag fees.