You could store a passenger entity, consisting of name/age/sex etc. (in a passenger entity table) and then your passenger booking table would simply contain the passenger entity ids (integers, GUIDs etc.). This is a form of normalisation.
However this may be an optimisation too far. Whether you do this really depends on how many duplicate entities etc. you have, and whether they're a real performance/management issue for you. e.g. do you expect to store more data for passengers (addresses, frequent flyer info etc.).