Frontier Airlines Cuts 21 Routes From The World’s Busiest Airport [Full List]

Frontier Airlines spent much of 2025 transforming Atlanta into one of the most important airports in its network. By December, the ultra-low-cost carrier was advertising 61 nonstop destinations from Hartsfield-Jackson Atlanta International Airport (ATL), having added domestic, Caribbean, Mexican and Central American routes at a rapid pace. Within months, Atlanta became the busiest airport in the Frontier network, eclipsing its long-time base at Denver International Airport (DEN).