Carrier route record
UABIL→DEN
United Airlines · Billings to Denver
- Flights
- 730
- Period
- July 2025 to June 2026
- Share of route
- 41%
- Carriers
- 2
Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with United Airlines.
United on BIL to DEN lands a B+, 5 points better than the national rate of 77.6%. About one flight in six 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 730 flights, with a median arrival 12 minutes early.
Set against the rest of the country, United's BIL to DEN record is 5 points better than the US average of 77.6%. That gap is worth roughly 51 fewer late arrivals for every thousand flights.
Key figures
On time
82.7%
Arrivals under 15 minutes late, of 724 completed flights
Avg delay
69 min
Across delayed arrivals only, not all flights
Cancelled
0.00%
National rate is 1.81%
Whole route
82.3%
Every carrier on BIL to DEN, 1,782 flights
These figures cover 730 flights between July 2025 and June 2026. The median arrival is 12 minutes early, which is the part an average hides: most flights here are fine, and the on-time rate is decided by a tail of badly late ones. On-time means under 15 minutes late, the DOT's own threshold.
Carrier by carrier
United against every carrier on BIL to DEN
United flew 730 of the 1,782 flights on BIL to DEN, about 41% of it. Its 82.7% on time is about level with the route as a whole at 82.3%. Ranked by on-time rate it is first of two carriers on the route, where the range runs from United at 82.7% to SkyWest at 81.9%.
Only one carrier clears this site's 365-flight floor here, so there is no comparison to draw. The table below is the full picture.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| United Airlines (this page) | 730 | 82.7% | 69 min | 0.00% | B+ |
| SkyWest Airlines | 1,052 | 81.9% | 82 min | 1.43% | B |
Flight by flight
United flight numbers on BIL to DEN
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 17 points, against half a point between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am365 flights91.0%
- 8am–11am—
- 11am–2pm8 flights—
- 2pm–5pm357 flights74.4%
- 5pm–8pm—
- 8pm–5am—
Scale runs 65% to 95%. Rows with fewer than 30 flights show a dash.
Book the early departure. Flights leaving between 5am–8am arrive on time 91.0% of the time, against 74.4% for the afternoon window. That is 17 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 5am–8am window is the busiest, with 365 flights scheduled in it.
Across the year
United on BIL to DEN through the year
August is the worst month at 62.9% on time, 35 points below April, the best at 98.3%. 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. January was the busiest month here, with 62 flights.
Across the week, Sunday is the strongest day at 91.3% on time and Saturday the weakest at 79.6%. 12 points is a smaller lever than departure hour, but it is free.
Delay causes
Why United 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 8,586 reported delay minutes.
- 34%Late-arriving aircraft
- 33%National Airspace System
- 24%Carrier
- 9%Extreme weather
34% 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 8,586 reported delay minutes here, that single category outweighs weather by 4 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 8,586 reported delay minutes.
33% 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 2,826 minutes out of 8,586, against a national NAS share of 21%.
Cancellations are rare at 0.00%, below the national 1.81% and low enough to earn the plus on the grade. Almost no flights are called off; the risk here is arriving late, not not arriving.
Connections and stage length
What a delay here costs
5.4% 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.
At 455 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 5am–8am window matters as much as it does.
The return leg is a different operation and performs like one: it runs 76.6% on time across 730 flights, 6 points below 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 6 points of difference.
One caution: this is a thin sample. 730 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 BIL to DEN
Put together: treat all of this as provisional. 730 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 82.7% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 724 completed flights over 12 months sit behind that.
Related
Where to go next
- BIL to DEN, every carrier
- United on DEN to BIL, the return leg
- SkyWest Airlines on BIL to DEN81.9%
- United Airlines network-wide record
- Denver International (DEN) delay statistics
- Why the first flight of the morning is statistically safest
- The best time of day to fly, according to 7.04 million flight records
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.