Do not make career decisions based on a desire to work at a specific airline. Few people who don't have family connections or extensive military fighter experience actually wind up at their #1 choice.

Target a specific tier of majors, ie big three, big six, LCC, etc. Your target should be big six or big three unless you have background issues which you know will be problematic (in that case can also target AA WO regionals).

It would be a catastrophic mistake to focus your efforts on one major (which might never call) when you could have been building seniority at another very similar major.

Make career decisions which will get you in the competitive range for the top employers as soon as possible.