The biggest backpack that fits every airline holds 39 litres
The largest backpack in our catalog that fits the carry-on limit of all 36 airlines we track is the JanSport Odyssey, at 39 litres. Not one of the 86 backpacks rated between 40 and 45 litres fits all 36. Most of them fit fewer than half.
So “40L carry-on backpack” is a promise that holds on most US and European airlines, not on all of them. If your trips include Ryanair, Qatar Airways or Emirates, the honest size for one bag is 36 to 39 litres.
How fit drops as volume grows
We grouped our 1,244 backpacks by stated volume and counted how many fit every airline, and how many fit at least 33 of the 36 (about 90%).
| Volume | Backpacks | Fit all 36 airlines | Fit 33 or more |
|---|---|---|---|
| Under 20 L | 287 | 87% | 90% |
| 20 to 24 L | 321 | 66% | 74% |
| 25 to 29 L | 249 | 43% | 58% |
| 30 to 34 L | 172 | 25% | 37% |
| 35 to 39 L | 96 | 10% | 27% |
| 40 to 44 L | 69 | 0% | 10% |
| 45 L and up | 50 | 0% | 2% |
Every 5 litres costs a large share of airlines: 87% of backpacks under 20 litres fit all 36, a quarter of those between 30 and 34 litres do, and none from 40 litres up. Past 40 litres, the question is no longer “does it fit every airline” but “which airlines will I give up”.
You can see the same curve for any airline you pick on our chart how big can I go?.
The largest backpacks that fit all 36
| Backpack | Volume | Weight | Size (cm) | US price |
|---|---|---|---|---|
| JanSport Odyssey | 39 L | 1.30 kg | 48 x 35 x 18 | $110 |
| Hynes Eagle Carry-On Travel Backpack 38L | 38 L | 0.80 kg | 50 x 33 x 20 | $45 |
| ALPAKA Traverse Backpack 38L | 38 L | 2.10 kg | 50 x 31 x 20 | $269 |
| Cabin Zero Classic Backpack 36L | 36 L | 0.70 kg | 45 x 31 x 20 | $100 |
| Cabin Zero Classic Tech Backpack 36L | 36 L | 0.77 kg | 45 x 31 x 20 | $125 |
| Cabin Zero Military Backpack 36L | 36 L | 1.03 kg | 47.5 x 32 x 17 | $142 |
| Gossamer Gear Fast Kumo 36 | 36 L | 0.61 kg | 45.7 x 27 x 11.4 | $190 |
| LOJEL Niru Journey Pack | 35 L | 0.80 kg | 50 x 35 x 14 | $190 |
| The North Face Base Camp Voyager | 35 L | 1.60 kg | 49 x 30.5 x 16 | $180 |
| Black Voyage Aero Pro | 35 L | 1.67 kg | 50 x 35 x 19 | $250 |
All of them are 50 cm long or less and 20 cm deep or less. That is the shape that clears Qatar Airways’ 50 cm length and Ryanair’s 20 cm depth at the same time. Weight varies more than size: the Cabin Zero Classic 36L holds nearly as much as the 38-litre ALPAKA Traverse for a third of the weight, while the ALPAKA has more structure and a 16-inch laptop compartment.
The 40 to 45 litre bags that miss only one airline
Qatar Airways is the reason. Its limit is 50 x 37 x 25 cm, and 50 cm is the shortest length any of our airlines allow. Drop Qatar, and several bigger backpacks fit the other 35:
- Pacsafe Venturesafe EXP45: 45 L, 55 x 33 x 19 cm, 1.8 kg.
- Cabin Zero ADV Backpack 42L and Classic Plus 42L: 42 L, 55 x 35 x 20 cm.
- Tortuga Lite Backpack 40L: 40 L, 55 x 35 x 20 cm, 1.6 kg.
- ULA Equipment UltraGrid Nexus: 40 L at 0.61 kg, the lightest of the group.
If you never fly Qatar, these are the largest “fits everywhere else” backpacks we know of.
Bigger bags for US airlines
If you fly only within the US, the common limit is 56 x 36 x 23 cm (22 x 14 x 9 in). The largest backpacks in our catalog that fit it are the ULA Equipment Camino at 54 litres (55.9 x 33 x 21 cm), the Shimoda Action X50 v2 at 50 litres, and the Osprey Sojourn Porter 46L. The ULA fits only 15 of our 36 airlines, so it is a US bag. The Osprey fits 30.
Popular “carry-on” backpacks, checked
Some well-known travel packs fit fewer airlines than their marketing suggests:
| Backpack | Volume | Size (cm) | Airlines it fits |
|---|---|---|---|
| Tortuga Lite Backpack 40L | 40 L | 55 x 35 x 20 | 35 of 36 |
| Aer Travel Pack 3 | 35 L | 54.5 x 33 x 21.5 | 31 of 36 |
| Osprey Farpoint 40 | 40 L | 51 x 36 x 20 | 28 of 36 |
| Tortuga Pro Backpack 40L | 40 L | 56 x 36 x 20 | 14 of 36 |
The Tortuga Pro is 1 cm longer and 1 cm wider than the Tortuga Lite, and that costs it 21 airlines, including United, Lufthansa and Air France. One centimetre matters when limits are this close.
How we counted
Volume is the brand’s stated capacity. Fit uses the brand’s published dimensions against each airline’s published limit, in any orientation. A full soft backpack can be deeper than its listed size, so a bag right at 20 cm may need to be packed below capacity to pass a strict sizer. Airline limits were checked in September and October 2026; see the methodology.