Dallas-based Southwest Airlines (WN) is the world's largest low-cost carrier. Southwest operates non-stop flights to more than 100 destinations across 10 countries. Unlike many major airlines, Southwest does not use hubs, but rather a point-to-point system. About 15 airports with a significant amount of WN flights have been designated as focus cities. The airline's fleet is configured with just an Economy Class cabin. In contrast to many low-cost carriers, Southwest does not charge a fee for up to two checked bags; non-alcoholic drinks and pretzels or peanuts are also free on board. Early boarding access, automatic online check-in and alcoholic beverages are available for purchase.