Carrier route record
F9DEN→ORD
Frontier Airlines · Denver to Chicago
- Flights
- 329
- Period
- July 2025 to June 2026
- Share of route
- 5%
- 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 ORD sits in the middle of the pack with a C. About seven flights in ten arrive on time by the DOT's definition, 9 points worse than the national rate of 77.6%. The late ones land an hour and a half behind schedule. That rests on 329 flights. The strongest carrier on the route with a full sample, American Airlines, flew 1,469 at 73.0% on time.
American Airlines is the most reliable of the three carriers covered here at 73.0% on time across 1,469 flights.
Key figures
On time
68.6%
Arrivals under 15 minutes late, of 325 completed flights
Avg delay
96 min
Across delayed arrivals only, not all flights
Cancelled
1.22%
National rate is 1.81%
Whole route
71.1%
Every carrier on DEN to ORD, 6,161 flights
These figures cover 329 flights between July 2025 and June 2026. Beyond the headline rate, 14.2% 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 ORD
Frontier flew 329 of the 6,161 flights on DEN to ORD, about 5% of it. Its 68.6% on time is 3 points worse than the route as a whole, which runs 71.1%. Ranked by on-time rate it is number four of five carriers on the route, where the range runs from Envoy at 74.0% to Southwest at 63.7%. One of those carriers flew fewer than 365 flights here, so treat their positions as rough.
The choice of carrier is not cosmetic here. American Airlines arrives on time 73.0% of the time; Southwest Airlines manages 63.7%. Sample sizes sit next to every figure, because a two-point gap across 482 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Envoy Airthin sample | 125 | 74.0% | 60 min | 0.80% | C+ |
| American Airlines | 1,469 | 73.0% | 124 min | 2.04% | C |
| United Airlines | 3,756 | 71.4% | 79 min | 0.75% | C+ |
| Frontier Airlines (this page)thin sample | 329 | 68.6% | 96 min | 1.22% | C |
| Southwest Airlines | 482 | 63.7% | 63 min | 0.62% | D+ |
American leads Southwest by 9 points. Real, but small enough that a better departure time on the weaker carrier can outweigh it.
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 32 points, against 9 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am52 flights94.2%
- 8am–11am10 flights—
- 11am–2pm6 flights—
- 2pm–5pm6 flights—
- 5pm–8pm88 flights62.1%
- 8pm–5am167 flights63.4%
Scale runs 55% to 100%. Rows with fewer than 30 flights show a dash.
The 5pm–8pm window is where this operation falls apart: 62.1% on time, against 94.2% for the 5am–8am slot. By evening the aircraft flying these rotations have absorbed a full day of small delays and there is no slack left to recover in. The 8pm–5am window is the busiest, with 167 flights scheduled in it.
Across the year
Frontier on DEN to ORD through the year
- Jul–Sep 2025116 flights71.3%
- Oct–Dec 202596 flights72.6%
- Jan–Mar 202648 flights68.1%
- Apr–Jun 202669 flights58.8%
Scale runs 50% to 80%. Rows with fewer than 30 flights show a dash.
Monthly volumes are too low here to break the year into twelve reliable readings. What the twelve-month total says is 68.6% on time across 329 flights.
Frontier on DEN to ORD did not run the same all year. Its best quarter was Oct–Dec 2025 at 72.6% on time and its weakest Apr–Jun 2026 at 58.8%, a swing of 14 points on roughly 82 flights a quarter. The twelve-month rate averages over that, so if you are flying in a weak quarter the quarter's own figure is the better guide.
Across the week, Wednesday is the strongest day at 84.8% on time and Sunday the weakest at 61.0%. 24 points is a smaller lever than departure hour, but it is free.
Delay causes
Why Frontier runs late on this route
Carriers report a reason for every delay minute they cause, in five DOT categories. The split below is by minutes, not by number of flights, so a handful of very long weather delays weighs as much as many short ones. It covers 9,802 reported delay minutes.
- 38%Late-arriving aircraft
- 28%National Airspace System
- 26%Carrier
- 7%Extreme weather
38% 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 9,802 reported delay minutes here, that single category outweighs weather by 5 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 9,802 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 94.2% on time here.
Cancellations sit at 1.22% against a national 1.81%, which is ordinary. Diversions add another 0.00%.
Connections and stage length
What a delay here costs
For anyone connecting, the number to weigh is not the on-time rate but the tail behind it. 14.2% of arrivals land a full hour or more behind schedule, against 8.1% nationally. A 45-minute layover does not survive that, and no amount of walking quickly changes it. Ninety minutes is the honest minimum here, and two hours if the onward flight is on a separate ticket.
The 888 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 is a different operation and performs like one: it runs 72.5% on time across 332 flights, 4 points above this direction. Departure banks, aircraft rotations and the congestion at each end all differ, so scoring the two directions together would average away a real 4 points of difference.
One caution: this is a thin sample. 329 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 ORD
Put together: treat all of this as provisional. 329 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 68.6% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 325 completed flights over 12 months sit behind that.
Related
Where to go next
- DEN to ORD, every carrier
- Frontier on ORD to DEN, the return leg
- Envoy Air on DEN to ORD74.0%
- American Airlines on DEN to ORD73.0%
- United Airlines on DEN to ORD71.4%
- Southwest Airlines on DEN to ORD63.7%
- Frontier Airlines network-wide record
- Denver International (DEN) delay statistics
- Chicago O'Hare International (ORD) delay statistics
- Why the first flight of the morning is statistically safest
- How often a connection fails at the major US hubs
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.