Carry-on

A carry-on is the primary bag you bring into the cabin instead of checking it, typically stored in the overhead bin or occasionally under the seat if it is small enough. Airlines each publish their own maximum dimensions and sometimes a weight limit, and these numbers are not standardized internationally, so a bag that is fine on one airline can be too large for another, especially on European and Asian budget carriers.

For one-bag travelers, the carry-on is usually a backpack rather than a rolling case, since a backpack keeps both hands free and is easier to carry up stairs, across cobblestones or through a crowded platform. Backpack style carry-ons also tend to compress a little at the gate if a sizer box is tight, which rigid rolling luggage cannot do.

When choosing one, check the exact linear inches or centimeters against the airlines you fly most, not just the largest one you have flown. Look for how the bag actually sits on your back when full, not just its listed volume. A common mistake is buying the biggest bag that is technically allowed and then filling it completely, which leaves no room for anything bought on the trip and makes the bag heavier than it needs to be.