REI Co-op Trail 25 Pack vs Waterfly Adventure Aether Backpack 25L
The REI Co-op Trail 25 Pack is 25L and 0.8kg1.8lb; the Waterfly Adventure Aether Backpack 25L is 25L and 0.8kg1.8lb. They weigh the same. The Waterfly Adventure Aether Backpack 25L costs $60.01 less. The REI Co-op Trail 25 Pack fits the carry-on limit of 36 of 36 major airlines and the Waterfly Adventure Aether Backpack 25L fits 36; under the seat, 1 and 0 of 26.
| Spec | REI Co-op Trail 25 Pack | Waterfly Adventure Aether Backpack 25L |
|---|---|---|
| Price | $100 | $39.99Best |
| Volume | 25L | 25L |
| Weight | 0.8kg1.8lb | 0.8kg1.8lb |
| Carry-on compliance | 100% | 100% |
| Personal-item compliance | 4%Best | 0% |
| Dimensions | 46×33×20cm18×13×8in | 47×31×16cm18.5×12×6.5in |
| Laptop | no laptop sleeve | 16" |
| Compartments | 1 | n/a |
| Bottle pockets | 2 | 2 |
| Opening | Panel access, top/panel | Zippered main compartment with two-way zippers |
| Warranty | No fixed term | 10 years |
| Organizer | No | No |
| Shoe compartment | No | No |
| Hydration sleeve | Yes | No |
| Frame sheet | Yes | No |
| Water-resistant | Yes | Yes |
| Rain cover | Yes | No |
| MOLLE | No | No |
| Hip belt | Removable | No |
| Sternum strap | No | Yes |
| Load lifters | No | No |
| Shoulder strap | No | No |
| Luggage pass-through | No | No |
| Camera compartment | No | No |
| Material | 210-denier ripstop nylon; lining: 200-denier recycled polyester; raincover: 70-denier nylon with polyurethane coating (all bluesign approved) | Polyester, polyester lining |
| Last checked | 2026-09 | 2026-10 |
Where their airline fit differs
| Airline | Limit | REI Co-op Trail 25 Pack | Waterfly Adventure Aether Backpack 25L |
|---|---|---|---|
| Frontier Airlines | Personal item | Fits | Too big |
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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.