sealandair

Hopefully posted in the correct category. Someone please explain or supply a link to how the money works at Part 121 carriers, since I as yet do not.

When going to the airline profile pages where an income calculator is featured, I see sliders for bid periods. What exactly is a bid period? Also, where it says a minimum of 70 credits offered per month, is that basically flight hours? My guess is that an "hour" can somehow be swapped for something else, thus making it a "credit".

I'm sure seniority somehow ties into all of this as well.

Thanks.