Aerolite Underseat backpack, maximum size
Soft profile · US carrier-sized
A soft-profile underseat backpack sized to the maximum personal-item allowance several named US carriers publish, listed with those airlines specifically in mind.
≈ $40
United Kingdom
Aerolite
Soft-profile underseat bags referenced against named US carriers
Aerolite markets its underseat bags against the specific personal-item dimensions published by several named airlines — useful as a reference point, though it’s worth checking that the named carriers match the airline actually being flown, since European carrier limits can differ from the US-focused references most often cited.
Its soft-sided construction can compress slightly at a borderline gate check, a genuine flexibility a rigid-sided bag doesn’t offer.