Aer Slim Pack 2 vs ALPAKA Metro Backpack (12L)
The Aer Slim Pack 2 is 12L and 0.82kg1.8lb; the ALPAKA Metro Backpack (12L) is 12L and 0.8kg1.8lb. The ALPAKA Metro Backpack (12L) is 0.02kg0lb lighter. The ALPAKA Metro Backpack (12L) costs $16 less. The Aer Slim Pack 2 fits the carry-on limit of 36 of 36 major airlines and the ALPAKA Metro Backpack (12L) fits 36; under the seat, 7 and 10 of 26.
| Spec | Aer Slim Pack 2 | ALPAKA Metro Backpack (12L) |
|---|---|---|
| Price | $125 | $109Best |
| Volume | 12L | 12L |
| Weight | 0.82kg1.8lb | 0.8kg1.8lbBest |
| Carry-on compliance | 100% | 100% |
| Personal-item compliance | 27% | 38%Best |
| Dimensions | 45×31×8cm17.5×12×3in | 42×25×15.5cm16.5×10×6in |
| Laptop | 16"Best | 14" |
| Compartments | n/a | 2 |
| Opening | n/a | wide-opening zip main compartment |
| Warranty | Lifetime | Lifetime |
| Organizer | Yes | Yes |
| Shoe compartment | No | No |
| Hydration sleeve | No | No |
| Frame sheet | No | No |
| Water-resistant | Yes | Yes |
| Rain cover | No | No |
| MOLLE | No | No |
| Hip belt | No | No |
| Sternum strap | No | No |
| Load lifters | No | No |
| Shoulder strap | No | No |
| Luggage pass-through | Yes | No |
| Camera compartment | No | No |
| Material | 1680D CORDURA ballistic nylon exterior (bluesign approved), 840D nylon face with weather-resistant coating, recycled nylon lining (bluesign approved), YKK zippers, Duraflex hardware | Axoflux 400D ripstop nylon exterior; Axoflux X-Grid 150D ripstop polyester interior; YKK AquaGuard zippers |
| Last checked | 2026-09 | 2026-09 |
Where their airline fit differs
| Airline | Limit | Aer Slim Pack 2 | ALPAKA Metro Backpack (12L) |
|---|---|---|---|
| Air Canada | Personal item | Too big | Fits |
| JetBlue Airways | Personal item | Too big | Fits |
| United Airlines | Personal item | Too big | Fits |
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Specs come from each brand's own product page. Fit uses listed dimensions in any orientation. How we score carry-on fit.