Hi, there could be many routes into an aerodynamics department. Depending upon the level of aerodynamic work you did at uni might mean that a company will take you directly and will teach you what you need to know. If you were to do postgrad work in the field, such as going to Cranfield in the UK then that would put you in a better bargaining position with companies. You would need to have experience of CFD work along with pen/paper type analysis. Youy could also sidetrack into the racing industry such working for companies such as Lotus etc, as teh skills are transferrable.
I cant give you any indication as to what the job entails on a daily basis, as i'm a stress engineer, not a aerodynamics one. But in general what we all do is pretty much the same on a daily basis: Size things and get ball-park answers, create a mathematical computer model (be it FE or CFD etc), then check again to make sure it makes sense. Then use the usual report writing and spreadsheet work.
This daily grind would probably only hold in a general work situation obviously.