I imagine so, as no flying class was ever mentioned past the one in Philospher's Stone, or was ther any O.W.L. for it. So, I don't even think it's considered a sub-subject, (Divintation, Care of Magical Creatures, Muggle Studies, Arithmancy, Ancient Runes)I think it's just something they review with first years a couple times for basic knowledge, as not many are Quidditch players and those who are seek knowledge from the team and other ways. We can't be sure, though.
Another opinion: I agree, because they were never mentioned outside the Sorcerer's Stone.