Carrier route record
F9DEN→DTW
Frontier Airlines · Denver to Detroit
- Flights
- 459
- Period
- July 2025 to June 2026
- Share of route
- 15%
- Carriers
- 5
Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with Frontier Airlines.
Frontier on DEN to DTW lands a B+, 3 points better than the national rate of 77.6%. About one flight in five arrives 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 459 flights. The strongest carrier on the route with a full sample, Delta Air Lines, flew 1,252 at 86.2% on time.
Delta Air Lines is the most reliable of the three carriers covered here at 86.2% on time across 1,252 flights.
Key figures
On time
80.3%
Arrivals under 15 minutes late, of 458 completed flights
Avg delay
76 min
Across delayed arrivals only, not all flights
Cancelled
0.22%
National rate is 1.81%
Whole route
77.6%
Every carrier on DEN to DTW, 3,088 flights
These figures cover 459 flights between July 2025 and June 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.
Carrier by carrier
Frontier against every carrier on DEN to DTW
Frontier flew 459 of the 3,088 flights on DEN to DTW, about 15% of it. Its 80.3% on time is 3 points better than the route as a whole, which runs 77.6%. Ranked by on-time rate it is number three of five carriers on the route, where the range runs from SkyWest at 100.0% to Southwest at 56.7%. One of those carriers flew fewer than 365 flights here, so treat their positions as rough.
The choice of carrier is not cosmetic here. Delta Air Lines arrives on time 86.2% of the time; Southwest Airlines manages 56.7%. Sample sizes sit next to every figure, because a two-point gap across 649 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| SkyWest Airlinesthin sample | 1 | 100.0% | — | 0.00% | A+ |
| Delta Air Lines | 1,252 | 86.2% | 75 min | 0.48% | A+ |
| Frontier Airlines (this page) | 459 | 80.3% | 76 min | 0.22% | B+ |
| United Airlines | 727 | 79.7% | 60 min | 0.00% | B+ |
| Southwest Airlines | 649 | 56.7% | 49 min | 1.08% | D |
The spread between Delta and Southwest is 30 points, wide enough that it should decide the booking. On a hundred trips that is 30 more arrivals inside the on-time window.
Departure window
When Frontier runs best on this route
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 26 points, against 30 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am147 flights93.2%
- 8am–11am25 flights—
- 11am–2pm58 flights81.0%
- 2pm–5pm47 flights76.1%
- 5pm–8pm154 flights66.9%
- 8pm–5am28 flights—
Scale runs 60% to 100%. Rows with fewer than 30 flights show a dash.
Book the early departure. Flights leaving between 5am–8am arrive on time 93.2% of the time, against 66.9% for the evening window. That is 26 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 5pm–8pm window is the busiest, with 154 flights scheduled in it.
Across the year
Frontier on DEN to DTW through the year
September is the best month on the calendar at 88.6% on time. Shoulder season thins the schedule and takes the summer weather with it, and the operation gets its margin back. June was the busiest month here, with 60 flights.
Across the week, Tuesday is the strongest day at 86.0% on time and Saturday the weakest at 74.0%. 12 points is a smaller lever than departure hour, but it is free.
Delay causes
Why Frontier runs late on this route
One category carries most of the weight here. Late-arriving aircraft accounts for 65% of the 6,871 delay minutes carriers reported, and the remaining four split what is left. The split is by minutes rather than by flights, so a few very long delays count for as much as many short ones.
- 65%Late-arriving aircraft
- 22%Carrier
- 10%National Airspace System
- 2%Extreme weather
65% 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 6,871 reported delay minutes here, that single category outweighs weather by 27 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. The split is drawn from 6,871 reported delay minutes.
The practical consequence: the 5am–8am departure is the one that starts clean. Its aircraft has no earlier leg to be late from, which is exactly why that window shows 93.2% on time here.
Cancellations are rare at 0.22%, below the national 1.81% 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.
Connections and stage length
What a delay here costs
8.3% of arrivals land an hour or more late, close to the national 8.1%. 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 last a little over an hour, which a normal layover absorbs.
The 1,123 miles between these two airports put this in the middle of the US network, around two and a half to three hours of block time. That is enough cruise to absorb a ten-minute late pushback and not enough to absorb thirty. It is also long enough that the aircraft usually flies three or four legs a day rather than six, which slows how fast delay compounds.
The return leg runs 83.2% on time across 459 flights, within 3 points of this direction. The two legs are scored separately because they usually differ; on this city pair they happen not to.
One caution: this is a thin sample. 459 flights over twelve months is enough to clear this site's floor but not enough to pin the rate down tightly, and a single bad week moves it by more than a point. Treat the grade as a rough reading.
What to do with this
Booking Frontier on DEN to DTW
Put together: treat all of this as provisional. 459 flights over twelve months is enough to clear this site's floor and not enough to be confident to better than a couple of points. The 80.3% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 458 completed flights over 12 months sit behind that.
Related
Where to go next
- DEN to DTW, every carrier
- Frontier on DTW to DEN, the return leg
- Delta Air Lines on DEN to DTW86.2%
- United Airlines on DEN to DTW79.7%
- Southwest Airlines on DEN to DTW56.7%
- Frontier Airlines network-wide record
- Denver International (DEN) delay statistics
- Detroit Metropolitan Wayne County (DTW) delay statistics
- Same route, different airline: where the carrier you pick matters most
- Why the first flight of the morning is statistically safest
Source: US DOT Bureau of Transportation Statistics, on-time performance data, July 2025 to June 2026. Last updated 15 September 2026; recomputed monthly. How this data is collected.