Currently, ATL doesn't look so junior. Bottom of the list not still in training has been based in Fresno and Denver. That could all change though over the next six months. If attrition stays the same we'll lose another 25% of our pilots. About half of those captains, the other first officers. Additionally, upgrade classes are being scheduled into September now. They'll be plenty of movement.

Base selection is done by a bid, in seniority order. You'll list the domiciles you want in order of preference. I believe when you are in Sim they are awarded based upon vacancies at that time. Not all domiciles will have vacancies. After that there is a system wide bid at the end of every month. Transfers and upgrades are awarded at that time. It's theoretically possible to change domiciles every month assuming openings and you have the seniority. You cannot bump someone out of a domicile, nor be bumped out once awarded one.

18 months with the company currently puts you at about 50% on the company wide seniority list.