Players: Delta Airlines would be the players because they have the highest interest in how customers are feeling about them. Moreover, they have the most power to change or react to it.
Context Setters: Flight attendants, ground crews, pilots would be in this category, but with a higher interest because they were the ones who were actually communicating and making the service dog get off the plane. They probably have some interest, since it would be important for them to know if that decision was right or not.
Subjects: The disabled man and other passengers would be subjects because the disabled man was treated very poorly, and they all have high interest in how Delta Airlines is going to react to this. They may also have some power to make changes by posting claims on social media.
Crowd: The crowd would be other airlines, people who don’t use Delta Airlines and or people who don’t ride an airplane that often. It is because this post does not affect them much.