Southwest Airlines and Delta Air Lines are fundamentally different in their business models, fleet structures, and service offerings. Delta is a legacy carrier that operates a "hub-and-spoke" system, funneling passengers through major hubs like Atlanta and Detroit to destinations worldwide using a diverse fleet of Airbus and Boeing aircraft. Delta offers multiple cabin classes, assigned seating, and is a member of the SkyTeam alliance. In contrast, Southwest is the world's largest low-cost carrier, famous for its "point-to-point" model and a fleet consisting exclusively of Boeing 737s. Southwest does not offer assigned seating; instead, passengers are assigned a boarding group and pick their own seats upon entering the plane. Additionally, Southwest offers unique perks like "two bags fly free" and no change fees, which are not standard on Delta's "Basic Economy" fares. While both are major U.S. airlines, Southwest focuses on domestic and near-international leisure travel, while Delta is a global full-service giant.