Aer Day Sling 4 vs ALPAKA Flight Sling Pro (2.5L)
The Aer Day Sling 4 is 2.5L and 0.34kg0.7lb; the ALPAKA Flight Sling Pro (2.5L) is 2.5L and 0.35kg0.8lb. The Aer Day Sling 4 is 0.01kg0lb lighter. The Aer Day Sling 4 fits the carry-on limit of 36 of 36 major airlines and the ALPAKA Flight Sling Pro (2.5L) fits 36; under the seat, 26 and 26 of 26.
| Spec | Aer Day Sling 4 | ALPAKA Flight Sling Pro (2.5L) |
|---|---|---|
| Price | $79 | $79 |
| Volume | 2.5L | 2.5L |
| Weight | 0.34kg0.7lbBest | 0.35kg0.8lb |
| Carry-on compliance | 100% | 100% |
| Personal-item compliance | 100% | 100% |
| Dimensions | 15×24×7.5cm6×9.5×3in | 18.5×27×6cm7.5×10.5×2.5in |
| Laptop | 8.3" | no laptop sleeve |
| Bottle pockets | n/a | 1 |
| Opening | Main compartment opens wide | zip main compartment |
| Warranty | Lifetime | Lifetime |
| Organizer | Yes | Yes |
| Shoe compartment | No | No |
| Hydration sleeve | No | No |
| Frame sheet | No | No |
| Water-resistant | No | 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 | No | No |
| Camera compartment | No | No |
| Material | 1680D CORDURA ballistic nylon exterior (bluesign approved), lightweight ripstop nylon interior (bluesign approved), YKK zippers, Duraflex hardware | Axoflux 400D ripstop nylon exterior; Axoflux X-Grid 150D ripstop polyester interior |
| Last checked | 2026-09 | 2026-09 |
Where their airline fit differs
Both bags pass and fail the same airline size limits.
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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.