Without further ado, here's how the very apprently non-biased rankings shake out, in descending order:
6. American Airlines
Alaska tops the list for the second straight year, in large part because it ranked in the top three across most categories, including "airfare, on-time arrivals, baggage handling, customer satisfaction and its best-in-the-industry frequent flyer program." Southwest, which unlike most airlines doesn't have a preternatural ability to gouge customers for every conceivable micro-service, ranked second for its lax policy on extra fees.
Some outliers definitely abound, here, the most prominent of which is Spirit. Complaining about Spirit, despite its ridiculously low fares, is something of a tradition, owing to its non-refund policy and hidden fees for nearly everything onboard the flight. Oddly, though, the model has resulted in good business over the years.