Is an Expandable Personal Item Backpack Worth It?
An expandable backpack promises the best of both: small enough to fly free under the seat, with a zip that opens for more room. Whether that is worth having depends on which kind of expansion you get, and on how you fly. Here is how to tell them apart.
Two kinds of expandable
Listings use the same word for two different designs.
Expands and stays under-seat size. The bag starts smaller than the limit and grows up to it. The ECOHUB is the clearest example: 18 x 12.7 x 6 inches closed, 18 x 12.7 x 8 inches open, going from about 22.6 to 30 litres. Even fully expanded it sits inside the common 18 x 14 x 8 inch personal item size, so there is nothing to remember at the gate.
Expands past the personal item into a carry-on. The bag is a full-size personal item zipped and a carry-on unzipped. The ZOMFELT expandable is 18 x 14 x 8 inches closed and grows 2 inches to 22 x 14 x 9, the standard US carry-on. Open, it no longer fits under the seat, and on a basic fare it becomes a paid bag.
The first kind is a convenience. The second kind is really two bags in one, with a rule attached.
When it is worth it
- Your trips vary. A weekend on a basic fare, then a week with a paid carry-on. One bag that zips down for the first and up for the second saves owning two.
- You come home with more than you left with. Expand on the return leg, when you have already paid for the bin or are checking a suitcase anyway.
- You pack light but want slack. The stay-under-seat kind gives you two inches of depth for a jacket or a souvenir, with no size risk.
- You also roll a suitcase. Both expandable bags we compared have a sleeve that slides over a suitcase handle, so the extra volume does not sit on your shoulders through the terminal.
When it is not
- You always fly basic fares. If the bag will never go in the bin, the carry-on-size expansion is weight you carry for nothing. The fixed-size ZOMFELT, at 18 x 14 x 8 inches and 0.8 kg, is the lightest bag in our comparison and holds 32 litres.
- You want the lightest bag. Expansion zips and the extra fabric add up. The expandable ZOMFELT is about 0.88 kg against 0.8 kg for its fixed-size sibling. Not much, but it is weight before you pack a thing.
- You overpack. An expansion zip is an invitation. A soft bag that is full at 8 inches deep and then unzipped to 10 will not go back under the seat without unpacking at the gate.
The gate mistake
Airlines that charge for bags measure them. The agent checks the bag as it is, not as it could be. If the expansion zip is open, the bag is measured open.
The safe habit is simple: zip the expansion closed before you leave for the airport on any basic fare, and pack so that it closes without force. If it only closes when you lean on it, it is a carry-on that day.
What to check in the listing
- Both sizes stated. Closed and open, in inches. A listing that gives only one number hides which one you are buying.
- Which dimension grows. Depth is the one airlines are strictest on. An expansion that adds depth beyond 8 inches takes the bag out of personal item territory; one that stays at 8 does not.
- The weight. Compare it with the fixed-size bags you are considering.
- What else is in the box. The ZOMFELT expandable includes three packing cubes, which is a reason to expand it in the first place.
The bottom line: worth it if your trips vary
An expandable personal item backpack is worth it if your trips are not all the same. Choose the stay-under-seat kind, like the ECOHUB, for extra room with no gate risk, and the carry-on-size kind if you sometimes pay for the bin and want one bag for both. If every flight is a basic fare, a lighter fixed-size bag does the same job for less weight.