Carry-On

Carry-on baggage is the bag you keep with you in the cabin rather than handing over at check-in. It is also sold as hand luggage, a cabin bag or simply a carry-on, and the four terms mean the same thing. It goes in the overhead locker or under the seat in front of you.

Most airlines now count two separate things. The personal item is small and lives under the seat: a handbag, a laptop bag, a small rucksack. The cabin bag is the larger wheeled or soft bag for the locker. On many budget fares only the personal item is included and the locker bag costs extra, which is the single most common reason a cheap fare stops being cheap at the gate.

There is no shared standard for the size. Each airline publishes its own dimensions and weight, the allowance can differ between two flights on the same ticket, and codeshare journeys usually follow the operating carrier rather than the one that sold you the seat. The practical approach is to check the smallest allowance on the whole itinerary and pack to that, because that is the one that will be enforced. Gate staff measure with a sizer when a flight is full and rarely when it is not, which makes the rule feel arbitrary even though it is not.

What cannot travel in the cabin is more consistent. Liquids above the container limit, anything sharp, and most tools will be taken at security. Power banks and spare lithium batteries are the reverse case: they are banned from checked luggage and must be in the cabin. Fragile items, medication, documents and a change of clothes belong in the cabin too, since that is the bag that cannot be delayed on a connection.

The weight limit is enforced more inconsistently than the size, and on smaller aircraft a full cabin means bags get taken at the gate regardless of compliance. If that happens, take the valuables and medication out before you hand it over. See baggage allowance for how this fits with checked bags, and fare class for why two passengers on the same aircraft can have different allowances.

Travelling cabin-only is a genuine strategy rather than a constraint. It removes the wait at the belt, removes the risk of a bag missing a tight connection, and on multi-stop trips it is usually the difference between moving easily and not. It also removes an argument, since two people with different packing habits tend to discover it at the airport rather than before.