Carrier route record
UACOS→DEN
United Airlines · Colorado Springs to Denver
- Flights
- 614
- Period
- July 2025 to June 2026
- Share of route
- 12%
- Carriers
- 3
Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with United Airlines.
United on COS to DEN sits in the middle of the pack with a C. About seven flights in ten arrive on time by the DOT's definition, 5 points worse than the national rate of 77.6%. The late ones land a little over an hour behind schedule. That rests on 614 flights. The strongest carrier on the route with a full sample, SkyWest Airlines, flew 3,282 at 81.3% on time.
The national on-time rate over the same period is 77.6%, so United on COS to DEN runs 5 points behind the country as a whole. Across a thousand flights that is about 47 extra late arrivals.
Key figures
On time
72.9%
Arrivals under 15 minutes late, of 606 completed flights
Avg delay
81 min
Across delayed arrivals only, not all flights
Cancelled
1.30%
National rate is 1.81%
Whole route
78.8%
Every carrier on COS to DEN, 5,038 flights
These figures cover 614 flights between July 2025 and June 2026. Beyond the headline rate, 10.7% 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
United against every carrier on COS to DEN
United flew 614 of the 5,038 flights on COS to DEN, about 12% of it. Its 72.9% on time is 6 points worse than the route as a whole, which runs 78.8%. Ranked by on-time rate it is last of three carriers on the route, where the range runs from SkyWest at 81.3% to United at 72.9%.
The choice of carrier is not cosmetic here. SkyWest Airlines arrives on time 81.3% of the time; Southwest Airlines manages 75.0%. Sample sizes sit next to every figure, because a two-point gap across 1,142 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| SkyWest Airlines | 3,282 | 81.3% | 75 min | 1.68% | B |
| Southwest Airlines | 1,142 | 75.0% | 57 min | 0.35% | B+ |
| United Airlines (this page) | 614 | 72.9% | 81 min | 1.30% | C |
SkyWest leads Southwest by 6 points. Real, but small enough that a better departure time on the weaker carrier can outweigh it.
Departure window
When United runs best on this route
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 25 points, against 6 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am153 flights82.1%
- 8am–11am—
- 11am–2pm138 flights87.0%
- 2pm–5pm323 flights62.5%
- 5pm–8pm—
- 8pm–5am—
Scale runs 55% to 90%. Rows with fewer than 30 flights show a dash.
The best window here is not the first bank but the 11am–2pm slot at 87.0% on time, ahead of 2pm–5pm at 62.5%. Where the curve peaks mid-day rather than at dawn, the constraint is usually congestion at one end rather than the aircraft's own rotation. The 2pm–5pm window is the busiest, with 323 flights scheduled in it.
Across the year
United on COS to DEN through the year
August is the worst month at 55.7% on time, 30 points below March, the best at 86.0%. 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. October was the busiest month here, with 63 flights.
Across the week, Sunday is the strongest day at 79.1% on time and Saturday the weakest at 64.4%. 15 points is a smaller lever than departure hour, but it is free.
Delay causes
Why United runs late on this route
One category carries most of the weight here. National Airspace System accounts for 44% of the 13,000 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.
- 44%National Airspace System
- 36%Late-arriving aircraft
- 15%Carrier
- 5%Extreme weather
36% 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 13,000 reported delay minutes here, that single category outweighs weather by 8 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 13,246 reported delay minutes.
44% of delay minutes are charged to the National Airspace System: air traffic volume, runway configuration, ground stops. No carrier can price its way out of that, which is why airport choice moves the number here more than carrier choice does. That is 5,863 minutes out of 13,000, against a national NAS share of 21%.
Cancellations sit at 1.30% 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. 10.7% 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.
At 73 miles this is a short hop, and stage length matters more than it looks. A flight this short spends under two hours in the air, which leaves almost nothing to claw back a late pushback with. Delay here is decided on the ground, in the turn, which is why the 11am–2pm window matters as much as it does.
The return leg is a different operation and performs like one: it runs 77.3% on time across 614 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. 614 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 United on COS to DEN
Put together: treat all of this as provisional. 614 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 72.9% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 606 completed flights over 12 months sit behind that.
Related
Where to go next
- COS to DEN, every carrier
- United on DEN to COS, the return leg
- SkyWest Airlines on COS to DEN81.3%
- Southwest Airlines on COS to DEN75.0%
- United Airlines network-wide record
- Denver International (DEN) 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.