Quite personally, I think that Season 3-8 of the Simpsons was the "Golden Era," which means that those season virtually had no bad episodes whatsoever. I actually think that this is one of the worst episodes in the "Golden Era." This is probably the worst episode of Season Six of the Simpsons, and Season Six is very good. Enough of badmouthing this episode, though, lets us talk about what is good about this episode. This had a very rich plot, and a unique one. It also had the cast of Cheers like you have seen them before.
Here is the plot of this episode. When Homer pretends to be a pilot and crashes a plane he is allowed a vacation anywhere. On the plane to the place Marge admits that she has a fear of flying. She starts to go insane. Marge goes to a therapist. She and the therapist try to dig deep down into her childhood to find out why she has a fear of flying. They find different reasons. Her father was a stewardess, she was chased by a crop-duster, and more. She is cured. Homer and Marge go on a plane, and it crashes.
Overall, this is not the best episode of the Simpsons. This is not my favorite but it did have a very good joke in my opinion. When Homer is kicked out of a bar a man that looks exactly like Homer and that talks like Homer comes in the bar. The people in the bar beat him up, thinking that it is Homer, but it turns about that he is Homer's exact double, but a dog has a fluffy tail and he goes after the dog. I did not really like the fluffy dog joke but the exact double joke was kind of funny. Anyway, this is not the best episode of the Simpsons to watch but it a lot better than all the episodes in Season Eleven.