The job is a full-time position.
Like Kev said, it is seniority based. Seniority is EVERYTHING in the airline business! As a new hire, as I said, you will be bidding amongst your classmates for a 8 hour (or in some cases 10) line. It will mostly be a relief line. But don't let that scare you, because some relief lines are pretty good for a new hire. Then, whenever the general bid comes up, (usually during scheduling changes) then you will bidding with everybody. Of course, you will be on the bottom of the list, but you never know what line you will be available to you. You might find yourself bidding on a work area; the bagroom (which is huge); or running bags inbounds or online; or working in the International dump; or other various duties here. Either a 8 hour shift (5 days on / 2 days off) or a 10 hour shift (4 days on / 3 days off). Mainly on the PM lines (don't even think about working AM, unless you are extremely lucky) PM starts at 1:00 pm (hence the PM name) There are various lines and shift times. All of that will be explained to you if and when you get the job. Oh, and after six months, if you want to go part time, you can put your bid card in for that too. We have a pretty good mix of part-timers and full-timers here.
As far as the Union goes:
TWU was shot down twice. (IMHO they made too many promises and everybody knows about the concessionary contract that AA has). It's very tricky here. You have a battle between the Northeast Stations (and EWR) who want some sort of Union representation, and Houston. (and some of the outstations too). It's a numbers game, and a lot of people like what we have here, since we got a pretty good management team who is very open and honest with us. Like other airlines, we all took hits too, but we are coming back with some of what we lost - without a Union. So it's a tough thing around here. IAM is trying now, and we'll see what happens. I don't think that the numbers are good. The ramp (and ATO - Passenger Services (ticket agents) are the only group on the property that is not unionized.