Editor's note: Their practicality, affordability, and level of service puts every other airline to shame, and we mean that. They’re the only U.S.-based airline that doesn’t charge for checked bags (up to two), and their rewards program is the best in the industry. Their business model has been written about extensively by authors like Jim Collins (Great by Choice), and it’s a model that keeps both customers and employees happy while still turning a profit. Enjoy some beautiful Southwest Airlines wallpapers!