Aer Day Sling 4 vs Sympl Motion Sling 3L
The Aer Day Sling 4 is 2.5L and 0.34kg0.7lb; the Sympl Motion Sling 3L is 3L and 0.34kg0.7lb. They weigh the same. The Aer Day Sling 4 costs $20 less. The Aer Day Sling 4 fits the carry-on limit of 36 of 36 major airlines and the Sympl Motion Sling 3L fits 36; under the seat, 26 and 26 of 26.
| Spec | Aer Day Sling 4 | Sympl Motion Sling 3L |
|---|---|---|
| Price | $79Best | $99 |
| Volume | 2.5L | 3L |
| Weight | 0.34kg0.7lb | 0.34kg0.7lb |
| Carry-on compliance | 100% | 100% |
| Personal-item compliance | 100% | 100% |
| Dimensions | 15×24×7.5cm6×9.5×3in | 16.5×25.4×7.6cm6.5×10×3in |
| Laptop | 8.3" | no laptop sleeve |
| Opening | Main compartment opens wide | n/a |
| 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 | Removable |
| 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 | CORDURA Re/Cor nylon (Carbonate), lining from recycled plastic bottles, YKK AquaGuard zippers |
| Last checked | 2026-09 | 2026-10 |
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.