In 2026, Hartsfield-Jackson Atlanta International Airport (ATL) has become the busiest airport for Frontier Airlines, overtaking the carrier’s operations at Denver. This has been calculated based on the number of seats the carrier has scheduled from its bases.
Frontier’s Denver operations have been almost consistent with the airline offering over four million seats per annum for the last five years. However, the airline has displayed significant capacity growth at its base in Atlanta, increasing its capacity by nearly 300% in the last half a decade.
Frontier’s Atlanta Operations Have Risen To The Top
The latest data from Cirium, an aviation analytics company, shows that Frontier’s operations at ATL this year, for the first time, have overtaken its operations at 
Denver International Airport (DEN), which has historically been the airline’s busiest base. The airline has over 4.48 million seats (one way) scheduled from Atlanta, which is 6.88% more capacity than the airline’s operations at Denver, which have over 4.1 million seats scheduled.
The airline’s operations at Denver have been quite consistent, with the carrier recording over four million seats for sale annually since 2019, with the lowest capacity of 3.5 million recorded in 2020 and the highest of 5.3 million recorded in 2024. However, the data trend shows an impressive growth in the airline’s capacity at Atlanta.
|
Airport |
Code |
Number Of Seats Scheduled (One-Way) In 2026 |
|---|---|---|
|
Atlanta Hartsfield-Jackson |
ATL |
4,484,950 |
|
Denver International Airport |
DEN |
4,196,212 |
|
Orlando Airport |
MCO |
3,971,268 |
|
Las Vegas Airport |
LAS |
2,830,408 |
|
Dallas Fort Worth |
DFW |
2,270,328 |
The airline’s current capacity of 4.48 million seats is 618% higher than the pre-pandemic levels, 287% higher than Frontier’s capacity five years ago, and 128% higher than the capacity recorded in 2025. When looking beyond Atlanta and Denver, all other Frontier bases have capacities below the four-million-passenger mark. The top five bases for Frontier are as detailed in the table below.
Statistics and data published by Road Genius show that the increase in capacity at the airline’s Atlanta base has resulted in Frontier now being the fastest-growing airline at the airport. It is also the second-largest airline there overall.
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Where Does Frontier Fly To From ATL?
As for the airline’s network from ATL, the data for the remainder of this year shows that Frontier will operate to nearly 40 destinations. By seat capacity (one-way), there are three routes on which the airline deploys over 120,000 seats, followed by another four routes with a capacity of above 90,000 seats. All remaining routes have lower seat capacity. However, three of the airline’s top ten routes (by capacity) are to the airline’s bases in Denver and Orlando, with Dallas.
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Another factor worth considering is that while Frontier grew its capacity, the market at Atlanta did see some shifts. Spirit Airlines was the fifth-largest carrier by capacity at ATL in 2025, and it ceased operations earlier this year. Furthermore, another strong airline, 
Southwest Airlines (the third-largest airline at ATL), has been periodically cutting its routes over the past few years.
Significant Route Reductions By Southwest
Recent data shows that Southwest has 26 fewer routes scheduled for the rest of the year compared to the past few years. While the airline did show recovery after the pandemic, the past few years have seen the number of flights reduce from over 36,000 departures in 2023 to just over 21,500 flights in 2025 and only 16,214 flights in 2026. However, before the pandemic, in 2019, the airline had a massive 40,550 departures from the base.
Atlanta, being the busiest airport in the world in terms of overall passenger numbers, is a very competitive base. Therefore, any reduction in the market would be replaced by an alternative operator. In the case of Frontier, a part of the airline’s capacity growth in recent years can definitely be attributed to the capacity decline of Southwest and Spirit.
Data published by The Engine Cowl indicates that the airline is constantly shifting capacity as required. This is why, during the months of February and March, the airline operated more weekly services from Denver. With that being said, Frontier is also careful in the routes that they operate. While its capacity has increased at ATL, Frontier has stopped operating on certain routes this year, compared to the same period in 2025.
