US-based low-cost carrier Southwest Airlines is unique in several different ways. The carrier is unquestionably the leader in low-cost aviation in the United States, much akin to Ryanair in Europe. The airline is the only carrier operating in the United States with a market share that comes even close to matching airlines like United Airlines,

Frontier Airlines is expanding its presence at Hartsfield-Jackson Atlanta International Airport (ATL) in a big way, with nine new routes launching between May and June.