That's how they manage to stay a "discount" airline.

I read an article a few years ago about the high price of air travel. Contrary to popular belief, air ticket prices have not risen that much, even in the past 20 years, compared to other service industries. I don't remember the actual percentage ticket prices have risen, but it really wasn't that much.

However, in order to keep ticket prices fairly stable, the airlines have systematically done away with various services - meals, pillows, blankets, staff - and have increased and implemented fees for what used to be routine offerings, checked baggage for instance.