Hyperlite Mountain Gear Aero 28 vs REI Co-op Flash Air 50
Weight and specs compared for 2026 — and which one to choose.
Ultralight 28L fastpack with vest-strap harness. Perfect for fast-and-light adventures and trail running.
Full details →Ultralight 50L pack with 3D contoured hip belt and ventilated back panel. Made from PFAS-free UHMWPE fabric with DWR coating.
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Hyperlite Mountain Gear Aero 28 vs REI Co-op Flash Air 50: which should you buy?
If saving weight is your priority, the Hyperlite Mountain Gear Aero 28 wins — at 536 g it is 332 g (38%) lighter than the REI Co-op Flash Air 50 (868 g). That said, the heavier option may justify the extra grams with more capacity, durability or comfort, so weigh the trade-off against how you'll use it.
See where both rank against everything else in this category on the lightest backpack page, or browse the full gear weight database.