1) The “quality” of spirit is just fine. They explicitly market themselves as a budget airline and that’s what you get. A lot of people just want the cheapest ticket to go from A to B and they provide it. Personally, I have enough disposable income to pay more for another airline, but sometimes the difference is so dramatic that I will take spirit. When I’m traveling with my two young kids, having a reclining seat and better flight attendants makes a marginal difference to an already difficult situation.
2) Their ticket prices are often a fraction of the others. Even if service quality is lower, I’d be surprised if it wasn’t pushing down overall prices.
