This is the allowance most travellers assume exists and mostly does not. Seven of the 11 major US carriers publish no carry-on weight limit whatsoever — the only practical test is whether you can lift the bag into the bin unaided. Four publish a number, and those four will weigh your bag if it looks heavy.
| # | Airline | Carry-on | Weight limit | Cost |
|---|---|---|---|---|
| 1 | Breeze Airways | 22 × 14 × 9 | 35 lb | Paid |
| 2 | Frontier Airlines | 24 × 16 × 10 | 35 lb | Paid |
| 3 | Sun Country Airlines | 24 × 16 × 11 | 35 lb | Paid |
| 4 | Alaska Airlines | 22 × 14 × 9 | None published | Free |
| 5 | Allegiant Air | 22 × 16 × 10 | None published | Paid |
| 6 | American Airlines | 22 × 14 × 9 | None published | Free |
| 7 | Delta Air Lines | 22 × 14 × 9 | None published | Free |
| 8 | Hawaiian Airlines | 22 × 14 × 9 | None published | Free |
| 9 | JetBlue | 22 × 14 × 9 | None published | Free |
| 10 | Southwest Airlines | 24 × 16 × 10 | None published | Free |
| 11 | United Airlines | 22 × 14 × 9 | None published | Depends on fare |
The three carriers with a published limit — Frontier at 35 lb, Breeze at 35 lb, Sun Country at 35 lb — are the ones to watch, and all three also charge for the bag. All three sit at the same 35 lb, so there is no ceiling to aim for beyond that one number. It is the kind of rule most likely to catch you out, because nothing about the bag’s size warns you. Every other US carrier here publishes none at all — though you still have to lift the bag into the bin yourself. Verified August 2026.
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Most do not. Frontier Airlines (35 lb), Breeze Airways (35 lb), Sun Country Airlines (35 lb) publish limits. The rest publish none — the practical test is whether you can lift the bag into the bin yourself.
Yes, without exception. Every US carrier includes one free under-seat personal item on every fare class, including Basic Economy and the cheapest ultra-low-cost fares. Only the overhead-bin carry-on ever costs extra.
Yes, on every US airline. They measure the outside of the bag, so wheels, handles, straps and external pockets all count. This is why a suitcase sold as a "20-inch carry-on" is often 22 inches overall.
Airlines revise baggage policy without announcement, usually alongside fare changes. Every figure here was checked against the carrier’s own published policy in August 2026 and each links to the source it came from.
Manufacturers publish dimensions inconsistently, and a “20-inch” spinner is almost never 20 inches once you count the wheels. Where a brand states dimensions including wheels and handles, that’s the number we use. Where it only publishes the case, we say so on the card. Airlines measure the outside of your bag — wheels, handles, straps and all. Anything marked borderline is down to the gate agent, and remember that a soft bag squashes into a sizer while a hard shell won’t.
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Limits verified August 2026 against each carrier’s published policy. Airlines change these without notice — always confirm before you fly. Spirit Airlines ceased operations on 2 May 2026 and is no longer listed.
Airline Bag Size Checker v1.0.15 · last updated 2026-08-12