Atlas Holdings is the plantation owner. Atlas, Polar and AACS all work side by side on the plantation. Since U.S. airlines are strictly controlled as to when they can strike by the NMB (the government), Atlas (only) is shortly going to be free to strike. The fear is that the work will just be shifted over to the other plantation workers, who (I'm afraid) will not be able legally to refuse the work.
I will add, just for a glimmer of hope, that US airlines generally have to go through the entire 30 day cooling off period before signing a contract. Maybe it's to ensure the best possible deal; maybe it's just to maximize the lawyers' fees....