Carrier performance at one airport

F9→DEN

Frontier Airlines at Denver International

Departures: 22,257
Period: June 2025 to May 2026
Routes: 25
Rank here: #4 of 9

Frontier Airlines at Denver lands a B+, level with the national rate of 77.4%. Roughly one flight in four arrive 15 minutes late or worse, and those flights are late by a little over an hour on average. That is a workable record, not a spotless one. That rests on 22,257 flights, of which Delta Air Lines flew 11,605 at 82.4% on time.

Measured against the airport rather than the country, Frontier Airlines runs about a point ahead of the 76.0% weighted average across all carriers at DEN. That is the comparison worth making: every operator here works the same runways, the same airspace and the same weather.

On time

77.1%

22,055 completed departures

Avg delay

68 min

Across delayed flights only

Cancelled

0.76%

At DEN, this carrier only

Rank here

Of 9 carriers clearing the floor at DEN

These figures cover 22,000 flights between June 2025 and May 2026. Beyond the headline rate, 8.3% of arrivals land a full hour or more behind schedule. That is the number that wrecks a connection, and it is not visible in an on-time percentage alone.

Against the competition

Every carrier at DEN, ranked

The choice of carrier is not cosmetic here. Delta Air Lines arrives on time 82.4% of the time; Allegiant Air manages 65.1%. Sample sizes sit next to every figure, because a two-point gap across 413 flights means less than a ten-point one.

On-time performance of all carriers departing DEN
Airline	Flights	On time	Avg delay	Cancelled	Grade
Delta Air Lines	11,605	82.4%	79 min	1.36%	B
SkyWest Airlines	75,448	79.4%	79 min	1.19%	B
United Airlines	106,792	78.2%	65 min	0.48%	B+
Frontier Airlines (this page)	22,257	77.1%	68 min	0.76%	B+
American Airlines	8,855	76.6%	104 min	2.03%	B
Alaska Airlines	2,642	74.3%	58 min	0.87%	C+
Southwest Airlines	89,073	69.6%	55 min	0.71%	C+
JetBlue Airways	1,242	69.0%	91 min	2.66%	C
Allegiant Air	413	65.1%	128 min	1.45%	C

The spread between Delta and Allegiant is 17 points, wide enough that it should decide the booking. On a hundred trips that is 17 more arrivals inside the on-time window.

Route by route

Where Frontier Airlines flies from DEN

Frontier Airlines operates 25 routes out of DEN with enough volume to report. Route records inside one carrier at one airport still spread widely, because a short shuttle and a transcontinental have very different exposure to a late inbound.

Frontier Airlines routes from DEN
Route	Flights	On time	Avg delay	Cancelled	Grade
DEN to LAS · Las Vegas	1,483	76.1%	70 min	0.88%	B+
DEN to PHX · Phoenix	1,401	76.5%	70 min	0.64%	B+
DEN to DFW · Dallas-Fort Worth	1,082	75.2%	70 min	0.92%	B+
DEN to SLC · Salt Lake City	995	80.6%	63 min	0.50%	B+
DEN to DCA · Washington	985	76.8%	79 min	0.81%	B+
DEN to MCO · Orlando	815	74.0%	72 min	1.23%	C
DEN to IAH · Houston	778	79.1%	63 min	0.13%	B+
DEN to LAX · Los Angeles	731	80.4%	72 min	0.82%	B+
DEN to SAN · San Diego	717	78.5%	66 min	0.84%	B+
DEN to ATL · Atlanta	710	78.9%	64 min	0.70%	B+
DEN to MSP · Minneapolis	607	70.3%	65 min	0.66%	C+
DEN to TPA · Tampa	598	81.3%	65 min	0.84%	B+
DEN to SFO · San Francisco	565	71.2%	59 min	0.88%	C+
DEN to ONT · Ontario	546	78.9%	65 min	0.37%	B+
DEN to AUS · Austin	521	72.0%	67 min	0.77%	C+
DEN to DTW · Detroit	446	77.3%	72 min	0.22%	B+
DEN to SEA · Seattle	412	72.1%	63 min	1.70%	C
DEN to CVG · Cincinnati	410	74.3%	72 min	1.22%	C
DEN to OKC · Oklahoma Citythin sample	357	73.2%	66 min	1.12%	C
DEN to SAT · San Antoniothin sample	357	79.4%	60 min	0.28%	B+
DEN to BNA · Nashvillethin sample	353	71.1%	63 min	0.57%	C+
DEN to MIA · Miamithin sample	345	71.8%	57 min	1.16%	C
DEN to PDX · Portlandthin sample	337	77.5%	66 min	0.89%	B+
DEN to ELP · El Pasothin sample	333	82.2%	63 min	0.60%	B+
DEN to ORD · Chicagothin sample	328	68.3%	100 min	0.91%	C+

Departure window

Best time of day for this operation

Departure time matters more here than the choice of carrier. The gap between the best and worst window is 21 points, against 17 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

5am–8am3,098 flights90.2%
8am–11am4,012 flights81.0%
11am–2pm3,378 flights80.2%
2pm–5pm3,630 flights74.7%
5pm–8pm2,193 flights71.4%
8pm–5am5,946 flights69.5%

Scale runs 60% to 95%. Rows with fewer than 30 flights show a dash.

Book the early departure. Flights leaving between 5am–8am arrive on time 90.2% of the time, against 69.5% for the overnight window. That is 21 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on.

Across the year

Seasonal pattern

Darker means more delays. Figures are on-time percentages.February best, June worst

June is the worst month at 63.5% on time, 22 points below February, the best at 85.1%. Summer afternoon convection and peak-season schedules land on the same weeks every year, so this is a pattern you can book around rather than a run of bad luck.

Delay causes

What holds this operation up

Late-arriving aircraft
41%
Carrier
36%
National Airspace System
20%
Extreme weather
3%

41% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. That is a cascade, and cascades start small and grow through the day. Across 343,000 reported delay minutes here, that single category outweighs weather by 13 to one. It is the strongest argument for booking the first departure of the morning, when the aircraft has been sitting at the gate overnight with nothing to inherit.

Cancellations are rare at 0.76%, below the national 1.80% and low enough to earn the plus on the grade. Roughly one flight in 100 is called off; the risk here is arriving late, not not arriving.

8.3% of arrivals land an hour or more late, close to the national 8.2%. That is the figure that decides a connection, and it says a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route are the a little over an hour kind, which a normal layover absorbs.

22,257 flights sit behind these numbers, which is a large enough sample that the headline rate is not moving on noise. Where a sub-group falls below 30 flights the site shows a dash instead of a percentage.

Put together: the calendar is the biggest lever here, not the carrier or the hour. February runs 85.1% on time and June 63.5%, a swing of 22 points. If the dates move at all, move them out of June before you think about anything else.

Common questions

Frontier Airlines at DEN

How often is Frontier Airlines at DEN delayed?

Roughly one flight in four arrive at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 22.9% of the 22,257 flights in this analysis, against 22.6% nationally. Delayed flights are late by a little over an hour on average.

Which airline is most reliable on Frontier Airlines at DEN?

Delta Air Lines leads at 82.4% on time across 11,605 flights. Allegiant Air is at the other end on 65.1%, a gap of 17 points. Sample size matters as much as the percentage: a rate built from a few hundred flights moves around far more than one built from ten thousand.

What time of day has the fewest delays on Frontier Airlines at DEN?

The 5am–8am departure window is the strongest at 90.2% on time. The 8pm–5am window is the weakest at 69.5%, 21 points behind. Later departures inherit delays from earlier flights the same aircraft has already flown, which is why the curve slopes the way it does.

How bad are June delays on Frontier Airlines at DEN?

June is the weakest month at 63.5% on time, compared with 85.1% in February. Across the year that is 22 points between the best and worst months. Moving flexible dates out of that month is one of the few things that reliably helps.

Where to go next

Source: US DOT Bureau of Transportation Statistics, on-time performance data, June 2025 to May 2026. Updated monthly. How this data is collected.

Key figures