Originally Posted by go skers

Voluntary TDY- You get a hotel and 24/7 per diem all month but can't bid your seniority in the TDY base. It's likely you'd be on reserve with this option. If you're junior and on reserve in your current base it can be a good option to pocket a $1400 per diem check and have a hotel all month to go explore NYC or ORD. A passes for travel to TDY are allowed

Involuntary TDY-You get a hotel and 24/7 per diem all month but are allowed to bid what your seniority can hold in the TDY base. For this upcoming month you'd have to be on the bottom of the list. It's unlikely you'd get it unless they TDY for a prolonged period of time like they did with ORD last winter and spring. Not a horrible thing if the base you get TDYed to is less senior than your current base. A passes for travel to TDY are allowed.

Home Based TDY- No hotel or 24/7 per diem but you get to bid what your seniority can hold in your TDY base. Commuters and even some locals that can access the TDY domicile use it if they get a seniority bump in the TDY base. Comes with A passes and you can also use the good faith commuter policy as well. Company likes it because it saves hotel and per diem money. Certain pilots like it for the possible seniority bump in the TDY domicile and maybe easier commuting especially on the back end for an A pass home.