ARNG=Army National Guard, ANG=Air National Guard

It's very rare for someone to fly for the Guard or Reserve after a full AD retirement. The problem is that you forfeit your retirement pay for every day you work in mil status for the Guard/Reserve. So, you would be working for half pay. There is some kind of waiver required I think. In my time as a Traditional Guardsman and Reservist, I never knew of anyone to go through with it.