If you're just starting out then don't even think of the Airline dream...you have many years ahead working in GA or other route before you have the relevant experience. In that time, and like most of us, after then, plan on minimum chance of taking birthdays, xmases etc off. Once in the airlines, you'll be bottom of the pile so expect days off commensurate with your position. Do your due diligence before starting out is my advice.