My wife is an FA for SWA, so I know that pilots can "buddy bid w/ other pilots to work the same line, and the same stands for FAs. However I am not sure if pilots and FAs can "buddy bid." I would say that my wife usually switches pilots once per day on average. Sometimes they share the same base, and sometimes not. Also, the pilots that she reports with in the morning are almost always different, than the ones from the night prior. That may just be the nature of the Southwest beast though, all of Southwest's in-flight crew work crazy schedules.