The British Airways hand baggage allowance is one cabin bag of up to 56cm x 45cm x 25cm and one little thing no greater than 40cm x 30cm x 15cm, each up to 23kg. Typically the bigger cabin bag will be placed into the above storage, however, it might be looked into the airplane hold on the off chance that there is not an adequate room ready, so this bag shouldn't contain any assets or medicine....