Like any major airline upgrade to Captain is based on date of hire seniority number. Now, some pilots bypass upgrade for better seniority on vacation, monthly bidding schedules and destinations.

At AA anything can happen. New hires can get the 757/767 or the S80 or 737. Until 2014 we still designate you Domestic or International. Our Caribbean monthly bid schedules for the last 7 years have included more and more Domestic flights and layovers.
In 2002 you might fly to Barbados, spend the night and fly home. 2 day trip. Well, now it's more likely Barbados layover (RON, remain overnight) then back to MIA then on to DFW spend the night, then either home on the 3rd day to MIA or you might go DFW to CUN (Cancun) then on to MIA.

I have overnighted in Quito Ecuador and then flown to MIA then on to Boston to spend the night.

It took me 15 years to get to be a 777 FO.

We have a monthly vacancy run. It's for 3 months ahead. So our next monthly vacancy run closes on July 5, we'll know on July 12th if we can change aircraft, seat (FO or CA) or Base for Sept 1. But at AA they make it weird and so the next vacancy run is for Aug 31.

They try to minimize 31 day months. So monthly bid schedules can be July 2-July 31.

February is usually Jan 31 - March 1.

If AA can make it complicated and then not explain it to you, they will.

We each have a monthly standing bid (a list on the computer of what you want)

Preferences they are called

Mine would be

777 CA
767 CA
737 CA
320 CA

777 FO
767 FO ect... you can change your choices whenever.

Not all the airlines run monthly vacancies. Some will wait till they need several Capt's or FO's in a base and then run one.

This is something I like about AA, you can change bases all the time. If there is a vacancy.

Last week they posted the vacancies for Aug 31. It was mostly for 737 CA's and FO's at most bases.

Recently we've had a lot of new vacancies on the 777 due to the 777-300's we're getting.

Hope I answered your queston.