Route reliability record
DEN→BIL
Denver to Billings
- Flights
- 1,774
- Period
- September 2025 to August 2026
- Distance
- 455 mi
- Carriers
- 2
This route lands a B+, 3 points better than the national rate of 77.3%. 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 rests on 1,774 DEN to BIL flights, of which SkyWest Airlines flew 1,049 at 81.1% on time.
Best time to fly DEN to BIL: a 8am–11am departure, ideally on a Tuesday. Flights in that window arrived on time 89.0% of the time and Tuesday flights 84.4%, against 80.3% for the route overall.
The US average over the same twelve months is 77.3%, so there is little to separate this route from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.
Key figures
On time
80.3%
Arrivals under 15 minutes late, of 1,752 completed flights
Avg delay
69 min
Across delayed arrivals only, not all flights
Cancelled
0.73%
National rate is 1.89%
Best carrier
SkyWest
81.1% on time across 1,049 flights
These figures cover 1,774 flights between September 2025 and August 2026. The median arrival is 6 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.
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Carrier by carrier
Which airline is most reliable on DEN to BIL
The two carriers here are closely matched: 2 points separate the best from the worst. At that spread, schedule and price are better tie-breakers than reliability. Sample sizes are shown so you can see which rows are worth weighing.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| SkyWest Airlines | 1,049 | 81.1% | 71 min | 1.14% | B |
| United Airlines | 725 | 79.2% | 68 min | 0.14% | B+ |
No carrier stands out. SkyWest tops the table at 81.1%, 2 points clear of the bottom, which is inside the range this kind of sample moves year to year.
Flight by flight
Flights on DEN to BIL
The flight numbers below flew this route at least 250 times in the period, busiest first. Each has its own record, with its schedule and delay causes.
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Best ways to make this trip
The most reliable ways to fly Denver to Billings
Every airline on this route, ranked by how often a scheduled flight actually operated and arrived on time, with its best departure time and most punctual flight number. No nearby airport pair beat these.
| Option | Airline | Success | On time | Cancelled | Best departure | Most punctual flight |
|---|---|---|---|---|---|---|
| 1. DEN → BILDenver to Billings | SkyWest Airlines | 80.2% | 81.1% | 1.14% | 8am–11am, Sat | OO 5498 15:35 |
| 2. DEN → BILDenver to Billings | United Airlines | 79.1% | 79.2% | 0.14% | 11am–2pm, Wed | UA 703 11:45 |
Success is the share of scheduled flights that operated and arrived less than 15 minutes late, so a cancelled flight counts against it. “(route)” means the best time comes from every carrier on the route rather than this airline alone.
Departure window
The best time of day to leave
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 14 points, against 2 points between the best and worst carrier.
- 5am–8am3 flights—
- 8am–11am360 flights89.0%
- 11am–2pm506 flights81.3%
- 2pm–5pm323 flights75.4%
- 5pm–8pm363 flights77.6%
- 8pm–5am219 flights75.6%
Scale runs 65% to 95%. Rows with fewer than 30 flights show a dash.
Book the morning departure. Flights leaving between 8am–11am arrive on time 89.0% of the time, against 75.4% for the afternoon window. That is 14 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 11am–2pm window is the busiest, with 506 flights scheduled in it.
Explore
Filter DEN to BIL by airline, time, month and day
Pick a breakdown and a carrier. The dashed mark on each row is the same slice for every US flight.
On DEN to BIL, the best departure window is 8am–11am at 89.0% on time and the worst is 2pm–5pm at 75.4%, a wide gap of 13.6 points. All US flights leaving 8am–11am ran 83.9%.
- 5–8am—
- 8–11am89.0%
- 11am–2pm81.3%
- 2–5pm75.4%
- 5–8pm77.6%
- 8pm–5am75.6%
best all US flightsScale 60% to 95%. Cells under 30 flights show a dash.
Across the year
When delays peak on this route
This route's year swings by 25 points from best month to worst, which is wide. An annual average tells you very little about the week you are actually flying, so read the strip rather than the headline if your dates are fixed.
August is the worst month at 66.5% on time, 25 points below October, the best at 91.0%. 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. July was the busiest month here, with 179 flights.
Across the week, Tuesday is the strongest day at 84.4% on time and Sunday the weakest at 75.7%, a spread of 9 points.
Delay causes
Why this route gets delayed
Late-arriving aircraft accounts for 47% of the 24,000 delay minutes carriers reported here, and the remaining four split what is left.
- 47%Late-arriving aircraft
- 33%Carrier
- 10%National Airspace System
- 9%Extreme weather
47% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 24,000 reported delay minutes here, that single category outweighs weather by 5 to one. The split is drawn from 23,951 reported delay minutes.
The practical consequence: the 8am–11am departure is the one that starts clean. Its aircraft has no earlier leg to be late from, which is exactly why that window shows 89.0% on time here.
Cancellations are rare at 0.73%, below the national 1.89% 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 actually costs
6.2% of arrivals land an hour or more late, close to the national 8.3%, so 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 8am–11am window matters as much as it does.
The return leg runs 82.5% on time across 1,774 flights, within 2 points of this direction. The two legs are scored separately because they usually differ; on this city pair they happen not to.
The sample behind these figures is 1,774 flights, enough that the headline rate is stable to within roughly a point. The hour-block and month splits divide that further, so read the thinner bars with more caution than the headline.
Work out the risk of missing a connection in BIL after this flight
What to do with this
Booking this route
Put together: the calendar is the biggest lever here, not the carrier or the hour. October runs 91.0% on time and August 66.5%, a swing of 25 points. If the dates move at all, move them out of August before you think about anything else. 1,752 completed flights over 12 months sit behind that.
Common questions
DEN to BIL questions
How often is DEN to BIL delayed?
About one flight in five arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 19.7% of the 1,774 flights in this analysis, against 22.7% nationally. Delayed flights are late by a little over an hour on average.
Which airline is most reliable on DEN to BIL?
SkyWest Airlines leads at 81.1% on time across 1,049 flights. United Airlines is at the other end on 79.2%, a gap of 2 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 DEN to BIL?
The 8am–11am departure window is the strongest at 89.0% on time. The 2pm–5pm window is the weakest at 75.4%, 14 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 August delays on DEN to BIL?
August is the weakest month at 66.5% on time, compared with 91.0% in October. Across the year that is 25 points between the best and worst months. Moving flexible dates out of that month is one of the few things that reliably helps.
Related
Where to go next
- BIL to DEN — the return legseparate record
- Denver International (DEN) delay statistics
- SkyWest Airlines on DEN to BIL81.1%
- United Airlines on DEN to BIL79.2%
- DEN to PHX, a related route75.6%
- SLC to BIL, a related route87.2%
- DEN to SLC, a related route78.2%
- SkyWest Airlines on-time record81.1%
- United Airlines on-time record79.2%
- Why the first flight of the morning is statistically safest
- The best time of day to fly, according to 7.05 million flight records
Direction matters. DEN to BIL and BIL to DEN are scored separately because they are separate operations, with different departure banks and different aircraft. Compare the return leg.
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Source: US DOT Bureau of Transportation Statistics, on-time performance data, September 2025 to August 2026. Last updated ; recomputed monthly. How this data is collected.