Small suitcases for the plane (size S) that you can find in this category are accepted by British Airways as so-called cabin baggage for overhead compartment. This means you can take your carry-on suitcase with you into the passenger cabin, store it in the overhead bin, and keep it close at hand and under your supervision without the need for check-in or paying additional fees. British Airways also offers a free under-seat bag option for passengers.
