Key Features
At 40L and 20.5×9.1×13.0 in, this backpack sits right at the upper limit of most airline carry-on allowances — so you get as much packing room as possible without ever having to check a bag.
A detachable rolltop pouch gives you a grab-and-go option for day trips, airport runs, or keeping essentials separate from your main pack.
The waxed P600 polyester canvas gives the Aion a refined, structured look that holds up to travel without looking like typical technical gear — at home in a boarding line or a business meeting.
Available in Black, Nutria Brown, and Dark Slate — all understated tones that work equally well for business or leisure travel.
Expert Take
If you're the type of traveler who refuses to check a bag, the Aion 40L is worth a close look. Forty liters is genuinely about as much as you can pack into a backpack and still walk straight to the gate — Thule has pushed this right to the carry-on limit. The removable rolltop bag is a nice bonus: leave it in your hotel room when you're exploring, or use it as a personal item under the seat in front of you. It's a well-thought-out bag for the one-bag travel crowd.