Which airlines make you pay for a cabin bag
On 15 of the 36 airlines we track, the cheapest ticket does not include a bag for the overhead bin. You get one small item that goes under the seat, and the cabin bag is either a paid extra or part of a higher fare. This is no longer only a budget-airline habit: Lufthansa, Air France, KLM, United and Air Canada do it too on their basic fares.
If you want to fly on the cheapest fare without paying extra, the bag you need is the one that fits the free under-seat size, not the carry-on size.
The 15 airlines, and what stays free
| Airline | When the cabin bag is not included | Free under-seat size | Bags that fit it |
|---|---|---|---|
| Ryanair | Every fare, unless you add Priority & 2 Cabin Bags | 40 x 30 x 20 cm | 237 |
| Wizz Air | Every fare, unless you add WIZZ Priority | 40 x 30 x 20 cm | 237 |
| Vueling | Unless you book the Fly Pro or Fly Grande bundle, or pay for it | 40 x 30 x 20 cm | 237 |
| Norwegian | LowFare tickets | 40 x 30 x 20 cm | 237 |
| easyJet | Unless you pay, or have easyJet Plus or an Inclusive Plus fare | 45 x 36 x 20 cm | 556 |
| Lufthansa | Economy Basic, short and medium-haul | 40 x 30 x 15 cm | 206 |
| Air France | Basic fares | 40 x 30 x 15 cm | 206 |
| KLM | Economy Basic tickets | 40 x 30 x 15 cm | 206 |
| United | Basic Economy, except to South America and across the Atlantic or Pacific | 43 x 25 x 22 cm (17 x 10 x 9 in) | 190 |
| Air Canada | Economy Basic bought from January 3, 2025, except when connecting to an international flight | 43 x 33 x 16 cm | 322 |
| WestJet | UltraBasic, except to and from Europe and Asia | 41 x 33 x 15 cm | 237 |
| Frontier | Every fare, unless your bundle includes it | 46 x 36 x 20 cm (18 x 14 x 8 in) | 659 |
| Allegiant | Every fare | 45 x 35 x 20 cm | 544 |
| Volaris | Zero and Básica fares | 45 x 35 x 20 cm | 544 |
| Avianca | Basic fares | Size not published | n/a |
“Bags that fit it” counts the bags in our catalog of 1,902 that fit the free size in any orientation. The wording of each rule is summarized from the airline’s own baggage page, which you will find on its airline page.
What the free bag looks like
The 40 x 30 x 20 cm club
Ryanair, Wizz Air, Vueling and Norwegian all give you a 40 x 30 x 20 cm (15.7 x 11.8 x 7.9 in) bag for free. 237 of our bags fit it, but only 76 of them are backpacks. Most backpacks are simply too tall. The median backpack in our catalog is 48 cm (18.9 in) long, and of the 1,168 backpacks that miss this size, 1,155 are longer than 40 cm. We go through the backpacks that do fit in the 40 x 30 x 20 cm free bag.
The thin European rule
Lufthansa, Air France and KLM keep 40 x 30 but cut depth to 15 cm (5.9 in). That is the strictest free size in Europe. A laptop sleeve, a slim tote or a packable daypack fits; a padded travel backpack usually does not. 206 bags pass, 50 of them backpacks.
The roomier American bag
Frontier, Allegiant and Volaris are stricter about the cabin bag but more generous under the seat: 45 or 46 cm long and 20 cm deep. 659 of our bags fit Frontier’s 46 x 36 x 20 cm, including 423 backpacks. Half of those hold 19 litres or more, and 211 hold at least 20 litres, which is enough for a light weekend.
United’s Basic Economy is the odd one out. Its 43 x 25 x 22 cm personal item is narrow, so only 190 bags fit, and just 35 backpacks. We compare the US limits in one personal item for every US airline.
How to fly the cheapest fare with one bag
- Find the free size for every airline on your trip. Connections count. A trip on Ryanair out and Lufthansa back needs a bag that fits 40 x 30 x 15 cm.
- Check the depth first. Free under-seat bags are 15 to 22 cm deep. A bag that is “only” 2 cm too deep is the most common reason to pay at the gate.
- Watch the weight. Wizz Air caps the free bag at 10 kg, and Norwegian, Air France and KLM count it inside a combined cabin allowance.
- Price the upgrade before you buy a new bag. If you only fly a budget airline once a year, paying for the cabin bag that trip can cost less than buying a second, smaller bag.
You can see which bags fit a given airline’s under-seat size on its airline page, or filter the catalog by airline with the under-seat option.
The rules change
Airlines change these rules more often than they change sizes. Air Canada’s Economy Basic rule, for example, applies only to tickets bought from January 3, 2025. We check the size limits weekly and recorded these fare rules in October 2026. Always read the fare details at booking: they are the final word.
SAS is not in the table on purpose. Its carry-on page says the allowance depends on the ticket type without naming the fares, so we did not guess. The other 20 airlines’ baggage pages either include a cabin bag on every fare or say nothing about fares.