The problem with NYC is that schedules tend to have poor commutability and almost everyone is a commuter, so it takes more relative seniority to get a good schedule. You can bid on any AE once on property (even in indoc). They happen irregularly, but usually 2-6 times per year. Once awarded it can take up to a year before you actually transfer to your new base/category. The seat lock (fleet bidding rules) are more complicated but have been well covered.