[rockostrich]

Low cost carriers are almost an entirely different industry than traditional airlines. For example, Frontier has a loyalty program as well as their "Go Wild" pass which is essentially "Movie Pass" for flying domestically in the US, but that operates as a loss leader for ancillaries, where they make most of their money (around $70 per passenger). As others have mentioned, RyanAir also has a loyalty program that they lose money on.

Traditional airlines are very much like Starbucks nowadays in that they are essentially banks, but low cost carriers are closer to movie theaters where they essentially make nothing selling the actual seat so the more people they get in the door, the more they can make on ancillaries.