In this job you will always be liable to fly at Christmas, until you become senior enough to ask for - and get - leave. That could take a very long time in some companies. Until you have that seniority, you are at the mercy of the roster - and you may only get that roster three or four weeks before Christmas. If you're not actually rostered to work Christmas Day, you may be returning from a trip late Christmas Eve, or outbound early Boxing Day morning. Or you could be on standby - which could be at an airport. Just tell your family to expect you when they see you!
Scroggs