Just a small correction.
In the States, to fly for an airline, you need an ATP; it is the law now.
And yes in other parts of the world the previous poster is correct in that you need a CPL to work for an airline; but that is just a minimum and competitive minimums are higher (i.e. ATP certificate etc).
In any case Arpan, in addition to having the appropriate pilots certificate, you need the RIGHT to WORK for that country. Good luck, choose wisely as to what you do; don't believe the hype from the flight schools; and DO NOT get into an obscene amount of debt to get into this profession.