dailynewsnblog
For many years, 
Denver International Airport (DEN) was overwhelmingly Frontier Airlines’ most-served airport. This was until the carrier launched its pan-US operation focused on point-to-point routes. When seats for sale are considered, DEN lost the throne to 
Hartsfield-Jackson Atlanta International Airport(ATL) this year, despite multiple routes being cut recently.
It was the first time that DEN was not the ultra-low-cost carrier’s top airport. Nonetheless, OAG shows that DEN has 9.5 million round-trip seats available in 2026, equivalent to 19% of the airline’s total capacity. That’s the lowest share ever and down from 21% last year. Significantly, it has fallen from as high as 92% as recently as 2010.
Frontier Has Cut These 19 DEN Routes This Year
Schedule analysis shows that all the following routes were operated by Frontier from DEN in 2026, but all have subsequently ended. No future services are planned, which is based on both examining flights from now until early May 2027. That is as far as the carrier’s schedule and booking engine currently extend.
13 of the airports have been removed from Frontier’s network completely, so, of course, they are no longer served from DEN. They are Cedar Rapids, Corpus Christi, Knoxville, Little Rock, Los Cabos, Madison, New York JFK (the airline’s final service will be from ATL in October), Puerto Vallarta, Seattle Paine Field, Sioux Falls, Tucson, Tulsa, and Spokane. It might have been easier to have stated those that are still on the airline’s map.
End Month In 2026 | Frontier From DEN To…* |
|---|---|
January | Chicago Midway, IL; New York JFK, NY; New York LaGuardia, NY; Seattle Paine Field, WA |
March | Los Cabos, MX; Pittsburgh, PA |
April | Milwaukee, WI; Puerto Vallarta, MX; Tucson, AZ; Tulsa, OK |
July | Spokane, WA |
August | Corpus Christi, TX; Knoxville, TN; Little Rock, AR; Richmond, VA |
September | Boise, ID; Cedar Rapids, IA |
October 2026 | Madison, WI; Sioux Falls, SD |
* Those that ended later in the year all had flights through 2026, but have zero scheduled at all in the future |
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17 Of The 19 Destinations Are Served By Other Airlines
When seats for sale are considered, DEN is the most-served airport for Frontier and 
Southwest Airlines, and is number two for 
United Airlines. As such, it is unsurprising that virtually all the 19 destinations that are no longer flown by Frontier are reachable with nonstop service by another operator.
United serves 15 of them, which is two more than Southwest. Then there are the others. Allegiant Air operates to Knoxville, 
Delta Air Lines serves New York JFK and LaGuardia, and JetBlue operates to JFK. LaGuardia and Knoxville have flights by three carriers. The former is served by Delta, Southwest, and United, while the latter is in the hands of Allegiant, Southwest, and United.
Only Corpus Christi and Seattle Paine Field are no longer flown from DEN. Until Frontier’s arrival, the coastal city in Texas did not have any flights from Colorado at all; more on that route below. However, Paine Field was in United’s network between 2019 and 2021.
Frontier From Denver To Corpus Christi
The ULCC flew to Corpus Christi twice-weekly between October 2025 and August 2026. The launch was significant, as it was the first time that the Texas city had a new destination in 27 years. Despite a revenue guarantee of $1.2 million, flights did not last long.
US Department of Transportation data for October 2025 to June 2026 (which is as far as data currently extends) shows that Frontier transported 13,307 passengers. As that’s just a number, it says little in itself. When seats for sale are included, the load factor was a ridiculously low 47.7%.
