Thule Aion Travel Backpack 28L × 
Allegiant Air personal item
Close.
Bag 18.5 x 11 x 9.1 in · Rule 18 x 14 x 8 in · high confidence
Bag reviewed 2026-05-28 · Rule reviewed 2026-05-28
Merchant links may earn us a commission. Confirm current retailer dimensions before buying.
Fit proof
Height
Over 0.5 in
Width
+3 in
Depth
Over 1.1 in
Rendered to scale from the reviewed dimensions above. Packed shape and gate enforcement can still change the outcome.
Why this answer
Thule Aion Travel Backpack 28L is over the published personal-item dimensions, but the soft construction may make it a borderline option if lightly packed. Treat this as a fee-risk result.
The selected rule is 18 x 14 x 8 in and the bag record is 18.5 x 11 x 9.1 in.
Next step
Thule Aion Travel Backpack 28L is borderline for Allegiant Air's personal item rule. Check the buying options only if the margin and packed-shape risk are acceptable.
Allegiant AirFits this rule with 1 inches of tightest margin.
1 in spare on height, the tightest side
17 x 13 x 6 in
Fits this rule with 0.1 inches of tightest margin.
0.1 in spare on depth, the tightest side
15.4 x 11.6 x 7.9 in
Fits this rule with 1 inches of tightest margin.
1 in spare on depth, the tightest side
16 x 12 x 7 in