SturdiBag Pro (Large, Flexible Height) — dimensions & which airlines it fits
SturdiBag Pro (Large, Flexible Height): 18 × 11.5 × 11.5 in external. The flexible-height top is the whole point — it compresses down to slide under lower seats, then springs back. A common pick for the 8.5" airlines (compresses; verify for your specific seat).
Specs
| External size (L×W×H) | 18 × 11.5 × 11.5 in |
| Type | soft-sided · flexible height |
Dimensions from the manufacturer product page · verified 2026-07-03
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Which airlines does the SturdiBag Pro (Large, Flexible Height) fit?
Compared against each airline's published under-seat limit (height strict; footprint may rotate). Green = within the published size; amber = fits only when collapsed / flexed; grey = over.
| Airline | Its limit | This carrier |
|---|---|---|
| Southwest Airlines | 18.5 × 13.5 × 8.5 in | Flexes — check height |
| Frontier Airlines | 18 × 14 × 11 in | Flexes — check height |
| Delta Air Lines | 18 × 11 × 11 in | Too big |
| JetBlue | 17 × 12.5 × 8.5 in | Too big |
| American Airlines | 18 × 11 × 11 in | Too big |
| United Airlines | 18 × 11 × 11 in | Too big |
| Alaska Airlines | 17 × 11 × 9.5 in | Too big |
| Air Canada | 17 × 16 × 8 in | Too big |
Compare carriers: all carriers · fit for a specific airline: Delta · JetBlue · American · United · Southwest