How Did Sabrina’s Parents Die on Netflix’s ‘The Chilling Adventures of Sabrina’?

Netflix’s Christmas special for The Chilling Adventures of Sabrina, called A Midwinter’s Tale, has premiered. The show revisits the death of Sabrina’s parents, which may leave you trying to remember just what happened to them. Here’s a quick recap. This, of course, will have spoilers for the first half of Season 1. The second half will premiere in April.
Sabrina’s parents died together in a plane crash. However, there appears to be some mystery connected to how they died that has not been revealed.
We learned in Season 1 that they were flying to Italy because her father, Edward, was supposed to be giving a lecture at the Vatican. On their way to Italy, their plane crashed and her mother, Diana Spellman, and her father, Edward Spellman, were killed.
At one point in the series, near the beginning, Prudence insinuated that there was more behind her parents’ deaths and it wasn’t really an accident. But we never find out what that was. However, most fans believe that something sinister happened with their plane crash.
At one point during the season, Sabrina learns that her mother is in limbo. This means that she still has some unfinished business keeping her spirit from moving on. Her mother was a human and her father was the High Priest. They were given permission by the Dark Lord to marry.
Later, during her dark baptism, Sabrina has a vision where she sees her parents standing over twins. That hasn’t been fully explained. Some believe that Sabrina has a twin somewhere out in the world. But others believe it was just symbolizing Sabrina’s own duality, showing her mortal side (with her mother baptizing her) and her immortal side when her father promised her to the Dark Lord.
Spoilers for A Midwinter’s Tale are below: 
In A Midwinter’s Tale, we learn that her parents were on Flight 231 when they crashed. It’s a strange moment, because Sabrina is trying to connect with her mom through a seance and she has to ask her mom a question that only her mother would know. Her mother tells her about the plane crash and the flight number. Since their deaths were so public in the witch community and her father was such an important figure, it really doesn’t make any sense that the information would be something only her mom would know.
Later, we learn that her mom didn’t pass over because she was worried Sabrina wouldn’t be cared for or loved like her mom could, but now she knows that’s not true and Sabrina has a lot of love and support.